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 = 7268 
WHERE 
  cscart_products_categories.product_id IN (
    89666, 88105, 88117, 88129, 88263, 89661, 
    88104, 88116, 88128, 88262, 88334, 
    89657, 88261, 89656, 89655, 88329, 
    88325, 88324, 88323, 94382, 94419, 
    94426, 94439, 94440, 94860, 94899, 
    94901, 94939, 94940, 94948, 95932, 
    96245, 96283, 96284, 96285, 96286, 
    96293, 96597, 96600, 100545, 100582, 
    100583, 100584, 100585, 100592, 101574, 
    101612, 101613, 101614, 101615, 101622
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.01554

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "80.39"
    },
    "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": 89,
            "rows_produced_per_join": 89,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "9.19",
              "eval_cost": "8.90",
              "prefix_cost": "18.09",
              "data_read_per_join": "1K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (89666,88105,88117,88129,88263,89661,88104,88116,88128,88262,88334,89657,88261,89656,89655,88329,88325,88324,88323,94382,94419,94426,94439,94440,94860,94899,94901,94939,94940,94948,95932,96245,96283,96284,96285,96286,96293,96597,96600,100545,100582,100583,100584,100585,100592,101574,101612,101613,101614,101615,101622))"
          }
        },
        {
          "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": 89,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "22.25",
              "eval_cost": "8.90",
              "prefix_cost": "49.24",
              "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": "22.25",
              "eval_cost": "0.45",
              "prefix_cost": "80.39",
              "data_read_per_join": "11K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}