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 (
    88212, 88236, 88240, 88503, 91445, 91459, 
    88678, 88725, 88534, 89459, 88979, 
    88996, 87465, 88499, 91455, 89022, 
    85672, 85692, 85704, 85716, 88169, 
    88217, 88528, 87514, 87530, 88452, 
    88469, 88485, 88985, 85680, 88663, 
    88710, 87453, 87464, 88502, 88677, 
    88724, 89575, 91444, 85727, 85744, 
    85754, 85764, 88770, 88198, 88210, 
    88235, 88239
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00189

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "79.76"
    },
    "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": 140,
            "rows_produced_per_join": 140,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "14.31",
              "eval_cost": "14.00",
              "prefix_cost": "28.31",
              "data_read_per_join": "2K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (88212,88236,88240,88503,91445,91459,88678,88725,88534,89459,88979,88996,87465,88499,91455,89022,85672,85692,85704,85716,88169,88217,88528,87514,87530,88452,88469,88485,88985,85680,88663,88710,87453,87464,88502,88677,88724,89575,91444,85727,85744,85754,85764,88770,88198,88210,88235,88239))"
          }
        },
        {
          "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": "35.00",
              "eval_cost": "0.70",
              "prefix_cost": "77.31",
              "data_read_per_join": "18K"
            },
            "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": "1.75",
              "eval_cost": "0.70",
              "prefix_cost": "79.76",
              "data_read_per_join": "112"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}