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 = 7165 
WHERE 
  cscart_products_categories.product_id IN (
    94311, 94312, 94313, 94314, 94315, 94316, 
    94317, 94318, 94319, 94320, 94321, 
    94322, 94323, 94324, 94325, 94326, 
    94327, 94328, 94329, 94330, 94331, 
    94332, 94381, 94838, 94849, 94958, 
    94965, 94966, 94967, 94968, 94969, 
    94970, 94971, 94972, 94973, 94974, 
    94975, 94976, 94977, 94978, 94979, 
    94980, 94981, 94982, 94983, 94984, 
    94985, 94986, 94987, 94988, 94989, 
    94990, 94991, 94992, 94993, 94994, 
    94995, 94996, 94997, 94998, 94999, 
    95000, 95001, 95002, 95003, 95004, 
    95005, 95006, 95007, 95008, 95009, 
    95010, 95011, 95012, 95013, 95014, 
    95015, 95016, 95017, 95018, 95019, 
    95020, 95021, 95022, 95023, 95024, 
    95025, 95026, 95027, 95028, 95029, 
    95030, 95031, 95032, 95033, 95034
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01662

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "89.39"
    },
    "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": 99,
            "rows_produced_per_join": 99,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "10.20",
              "eval_cost": "9.90",
              "prefix_cost": "20.10",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (94311,94312,94313,94314,94315,94316,94317,94318,94319,94320,94321,94322,94323,94324,94325,94326,94327,94328,94329,94330,94331,94332,94381,94838,94849,94958,94965,94966,94967,94968,94969,94970,94971,94972,94973,94974,94975,94976,94977,94978,94979,94980,94981,94982,94983,94984,94985,94986,94987,94988,94989,94990,94991,94992,94993,94994,94995,94996,94997,94998,94999,95000,95001,95002,95003,95004,95005,95006,95007,95008,95009,95010,95011,95012,95013,95014,95015,95016,95017,95018,95019,95020,95021,95022,95023,95024,95025,95026,95027,95028,95029,95030,95031,95032,95033,95034))"
          }
        },
        {
          "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": 99,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "24.75",
              "eval_cost": "9.90",
              "prefix_cost": "54.75",
              "data_read_per_join": "1K"
            },
            "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": 4,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "24.75",
              "eval_cost": "0.50",
              "prefix_cost": "89.40",
              "data_read_per_join": "12K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}