SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids, 
  product_position_source.position AS position 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_products_categories AS product_position_source ON cscart_products_categories.product_id = product_position_source.product_id 
  AND product_position_source.category_id = 7148 
WHERE 
  cscart_products_categories.product_id IN (
    100847, 100848, 100853, 100854, 100855, 
    100856, 100863, 100864, 100865, 100866, 
    100871, 100872, 100873, 100874, 100875, 
    100876, 100971, 100972, 100973, 100974, 
    100975, 100976, 100977, 100978, 100979, 
    100980, 100981, 100982, 100983, 100984, 
    100988, 101011, 101012, 101013, 101014, 
    101015, 101016, 101017, 101018, 101019, 
    101020, 101021, 101054, 101102, 101103, 
    101104, 101625, 101628, 101629, 101630, 
    101631, 101632, 101633, 101635, 101636, 
    101637, 101638, 101639, 101640, 101644, 
    101645, 101646, 101647, 101648, 101649, 
    101650, 101651, 101652, 101653, 101656, 
    101657, 101658, 101659, 101669, 101670, 
    101672, 101673, 101674, 101675, 101676, 
    101677, 101678, 101679, 101680, 101681, 
    101684, 101685, 101686, 101687, 101688, 
    101689, 101690, 101691, 101692, 101693, 
    101694
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00242

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "132.00"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "link_type",
              "pt"
            ],
            "key": "pt",
            "used_key_parts": [
              "product_id"
            ],
            "key_length": "3",
            "rows_examined_per_scan": 232,
            "rows_produced_per_join": 232,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "23.54",
              "eval_cost": "23.20",
              "prefix_cost": "46.74",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (100847,100848,100853,100854,100855,100856,100863,100864,100865,100866,100871,100872,100873,100874,100875,100876,100971,100972,100973,100974,100975,100976,100977,100978,100979,100980,100981,100982,100983,100984,100988,101011,101012,101013,101014,101015,101016,101017,101018,101019,101020,101021,101054,101102,101103,101104,101625,101628,101629,101630,101631,101632,101633,101635,101636,101637,101638,101639,101640,101644,101645,101646,101647,101648,101649,101650,101651,101652,101653,101656,101657,101658,101659,101669,101670,101672,101673,101674,101675,101676,101677,101678,101679,101680,101681,101684,101685,101686,101687,101688,101689,101690,101691,101692,101693,101694))"
          }
        },
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "nuie_scalesta_net.cscart_products_categories.category_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 11,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "58.00",
              "eval_cost": "1.16",
              "prefix_cost": "127.94",
              "data_read_per_join": "30K"
            },
            "used_columns": [
              "category_id",
              "usergroup_ids",
              "status",
              "storefront_id"
            ],
            "attached_condition": "((`nuie_scalesta_net`.`cscart_categories`.`storefront_id` in (0,1)) and ((`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`nuie_scalesta_net`.`cscart_categories`.`usergroup_ids`))) and (`nuie_scalesta_net`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "product_position_source",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id",
              "product_id"
            ],
            "key_length": "6",
            "ref": [
              "const",
              "nuie_scalesta_net.cscart_products_categories.product_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 11,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.90",
              "eval_cost": "1.16",
              "prefix_cost": "132.00",
              "data_read_per_join": "185"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}