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 = 7210 
WHERE 
  cscart_products_categories.product_id IN (
    88064, 88568, 88957, 88958, 88986, 88168, 
    88216, 89842, 89894, 89967, 91533, 
    84770, 84783, 84792, 87538, 88418, 
    89787, 89791, 88754, 88942, 85664, 
    85684, 85696, 85708, 85669, 85689, 
    85701, 85713, 88969, 88970, 88973, 
    88974, 85730, 85747, 85757, 85767, 
    84765, 85660, 85677, 88554, 88660, 
    88661, 88707, 88708, 85721, 85738, 
    85748, 85758
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00233

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "84.30"
    },
    "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": 148,
            "rows_produced_per_join": 148,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "15.11",
              "eval_cost": "14.80",
              "prefix_cost": "29.91",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (88064,88568,88957,88958,88986,88168,88216,89842,89894,89967,91533,84770,84783,84792,87538,88418,89787,89791,88754,88942,85664,85684,85696,85708,85669,85689,85701,85713,88969,88970,88973,88974,85730,85747,85757,85767,84765,85660,85677,88554,88660,88661,88707,88708,85721,85738,85748,85758))"
          }
        },
        {
          "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": 7,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "37.00",
              "eval_cost": "0.74",
              "prefix_cost": "81.71",
              "data_read_per_join": "19K"
            },
            "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": 7,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.85",
              "eval_cost": "0.74",
              "prefix_cost": "84.30",
              "data_read_per_join": "118"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}