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 = 7195 
WHERE 
  cscart_products_categories.product_id IN (
    100858, 100859, 100860, 100861, 100862, 
    100867, 100868, 100869, 100870, 100877, 
    100878, 101055, 101056, 101057, 101058, 
    101059, 101060, 101061, 101062, 101063, 
    101064, 101065, 101066, 101067, 101068, 
    101069, 101070, 101071, 101072, 101073, 
    101074, 101075, 101076, 101077, 101078, 
    101079, 101080, 101081, 101082, 101083, 
    101084, 101085, 101086, 101087, 101088, 
    101089, 101090, 101091
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00158

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "48.88"
    },
    "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": 54,
            "rows_produced_per_join": 54,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "5.68",
              "eval_cost": "5.40",
              "prefix_cost": "11.08",
              "data_read_per_join": "864"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (100858,100859,100860,100861,100862,100867,100868,100869,100870,100877,100878,101055,101056,101057,101058,101059,101060,101061,101062,101063,101064,101065,101066,101067,101068,101069,101070,101071,101072,101073,101074,101075,101076,101077,101078,101079,101080,101081,101082,101083,101084,101085,101086,101087,101088,101089,101090,101091))"
          }
        },
        {
          "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": 54,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "13.50",
              "eval_cost": "5.40",
              "prefix_cost": "29.98",
              "data_read_per_join": "864"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        },
        {
          "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": 2,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "13.50",
              "eval_cost": "0.27",
              "prefix_cost": "48.88",
              "data_read_per_join": "7K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}