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 = 7237 
WHERE 
  cscart_products_categories.product_id IN (
    90813, 90814, 89717, 89718, 90812, 89716, 
    90810, 90811, 89714, 89715, 88295, 
    89695, 88289, 88294, 88113, 88125, 
    88137, 89689, 89694, 88111, 88112, 
    88123, 88124, 88135, 88136, 88110, 
    88122, 88134, 88287, 88288, 88290, 
    88291, 88292, 88293, 88386, 88387, 
    89687, 89688, 89690, 89691, 89692, 
    89693, 88285, 88286, 88385, 88283, 
    88284, 89685
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01593

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "106.50"
    },
    "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": 118,
            "rows_produced_per_join": 118,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "12.10",
              "eval_cost": "11.80",
              "prefix_cost": "23.90",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (90813,90814,89717,89718,90812,89716,90810,90811,89714,89715,88295,89695,88289,88294,88113,88125,88137,89689,89694,88111,88112,88123,88124,88135,88136,88110,88122,88134,88287,88288,88290,88291,88292,88293,88386,88387,89687,89688,89690,89691,89692,89693,88285,88286,88385,88283,88284,89685))"
          }
        },
        {
          "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": 118,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "29.50",
              "eval_cost": "11.80",
              "prefix_cost": "65.20",
              "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": 5,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "29.50",
              "eval_cost": "0.59",
              "prefix_cost": "106.50",
              "data_read_per_join": "15K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}