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 = 7194 
WHERE 
  cscart_products_categories.product_id IN (
    99000, 99001, 99002, 99003, 99004, 99005, 
    99006, 99007, 99008, 99009, 99010, 
    99011, 99333, 99334, 99335, 99336, 
    99337, 99338, 99339, 99340, 99341, 
    99342, 99343, 99491, 99492, 99493, 
    99494, 99495, 99496, 99497, 99498, 
    99499, 99500, 99501, 99502, 99503, 
    99504, 99505, 99506, 100399, 100479, 
    100501, 100502, 100853, 100854, 100855, 
    100863, 100864, 100865, 100866, 100871, 
    100872, 100873, 100874, 100875, 100876, 
    101054, 101656, 101657, 101658, 101659
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00239

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "34.90"
    },
    "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": 61,
            "rows_produced_per_join": 61,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "6.38",
              "eval_cost": "6.10",
              "prefix_cost": "12.48",
              "data_read_per_join": "976"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99000,99001,99002,99003,99004,99005,99006,99007,99008,99009,99010,99011,99333,99334,99335,99336,99337,99338,99339,99340,99341,99342,99343,99491,99492,99493,99494,99495,99496,99497,99498,99499,99500,99501,99502,99503,99504,99505,99506,100399,100479,100501,100502,100853,100854,100855,100863,100864,100865,100866,100871,100872,100873,100874,100875,100876,101054,101656,101657,101658,101659))"
          }
        },
        {
          "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": 3,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "15.25",
              "eval_cost": "0.31",
              "prefix_cost": "33.83",
              "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')))"
          }
        },
        {
          "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": 3,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.76",
              "eval_cost": "0.31",
              "prefix_cost": "34.90",
              "data_read_per_join": "48"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}