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 = 7320 
WHERE 
  cscart_products_categories.product_id IN (
    89976, 89977, 89978, 89979, 89980, 89981, 
    88069, 88068, 88067, 88083, 87938, 
    87941, 87988, 88052, 88053, 88054, 
    87990, 87961, 87959, 87998, 88000, 
    88031, 87945, 87942, 87964, 88018, 
    88021, 88006, 88013, 88015, 87972, 
    87944, 88154, 94484, 94486, 94487, 
    94488, 94489, 94490, 94491, 94493, 
    94494, 94505, 94506, 94507, 94509, 
    94511, 94512, 94513, 94516, 94517, 
    94518, 94519, 94520, 94521, 94522, 
    94523, 94524, 94525, 94526, 94527, 
    94528, 94529, 94530, 94531, 94532, 
    94533, 94534, 94535, 94536, 94537, 
    94538, 94539, 94540, 94541, 94542, 
    94543, 94544, 94545, 94546, 94547, 
    94548, 94549, 94550, 94551, 94552, 
    94553, 94554, 94555, 94556, 94557, 
    94573, 94575, 94576, 94577, 94578
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00258

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "109.29"
    },
    "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": 192,
            "rows_produced_per_join": 192,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "19.53",
              "eval_cost": "19.20",
              "prefix_cost": "38.73",
              "data_read_per_join": "3K"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (89976,89977,89978,89979,89980,89981,88069,88068,88067,88083,87938,87941,87988,88052,88053,88054,87990,87961,87959,87998,88000,88031,87945,87942,87964,88018,88021,88006,88013,88015,87972,87944,88154,94484,94486,94487,94488,94489,94490,94491,94493,94494,94505,94506,94507,94509,94511,94512,94513,94516,94517,94518,94519,94520,94521,94522,94523,94524,94525,94526,94527,94528,94529,94530,94531,94532,94533,94534,94535,94536,94537,94538,94539,94540,94541,94542,94543,94544,94545,94546,94547,94548,94549,94550,94551,94552,94553,94554,94555,94556,94557,94573,94575,94576,94577,94578))"
          }
        },
        {
          "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": 9,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "48.00",
              "eval_cost": "0.96",
              "prefix_cost": "105.93",
              "data_read_per_join": "25K"
            },
            "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": 9,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "2.40",
              "eval_cost": "0.96",
              "prefix_cost": "109.29",
              "data_read_per_join": "153"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}