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 = 7186 
WHERE 
  cscart_products_categories.product_id IN (
    94732, 94736, 94740, 94744, 94748, 96305, 
    96306, 96307, 96309, 96312, 96315, 
    96317, 96320, 96322, 96324, 96326, 
    96328, 96330, 96332, 96335, 96339, 
    97016, 97022, 97023, 97026, 97030, 
    97032, 97039, 97045, 97833, 97843, 
    97847, 97852, 97856, 97860, 97864, 
    97868, 97872, 97890, 97891, 97892, 
    97893, 97894, 97895, 97896, 97897, 
    97898, 97899, 97900, 97901, 97902, 
    97915, 97916, 97917, 97918, 97919, 
    97920, 97921, 97922, 97923, 97924, 
    97925, 97926, 97927, 97928, 97929, 
    97930, 97931, 97932, 97933, 97934, 
    97947, 97948, 97949, 97950, 97951, 
    97960, 97961, 97964, 97965, 97966, 
    97969, 97974, 97976, 97977, 97980, 
    97981, 97984, 97985, 98040, 98042, 
    98044, 98046, 98048, 98050, 98085
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00216

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "54.77"
    },
    "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": 96,
            "rows_produced_per_join": 96,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "9.89",
              "eval_cost": "9.60",
              "prefix_cost": "19.49",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (94732,94736,94740,94744,94748,96305,96306,96307,96309,96312,96315,96317,96320,96322,96324,96326,96328,96330,96332,96335,96339,97016,97022,97023,97026,97030,97032,97039,97045,97833,97843,97847,97852,97856,97860,97864,97868,97872,97890,97891,97892,97893,97894,97895,97896,97897,97898,97899,97900,97901,97902,97915,97916,97917,97918,97919,97920,97921,97922,97923,97924,97925,97926,97927,97928,97929,97930,97931,97932,97933,97934,97947,97948,97949,97950,97951,97960,97961,97964,97965,97966,97969,97974,97976,97977,97980,97981,97984,97985,98040,98042,98044,98046,98048,98050,98085))"
          }
        },
        {
          "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": "24.00",
              "eval_cost": "0.48",
              "prefix_cost": "53.09",
              "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')))"
          }
        },
        {
          "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": 4,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.20",
              "eval_cost": "0.48",
              "prefix_cost": "54.77",
              "data_read_per_join": "76"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}