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 = 7195 
WHERE 
  cscart_products_categories.product_id IN (
    99303, 99304, 99305, 99306, 99307, 99308, 
    99309, 99310, 99311, 99312, 99319, 
    99320, 99321, 99356, 99357, 99358, 
    99359, 99360, 99361, 99362, 99363, 
    99364, 99365, 99366, 99367, 99368, 
    99374, 99375, 99376, 99377, 99378, 
    99379, 99380, 99381, 99382, 99383, 
    99384, 99385, 99386, 99387, 99388, 
    99389, 99390, 99391, 99392, 99393, 
    99394, 99395
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "46.18"
    },
    "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": 51,
            "rows_produced_per_join": 51,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "5.38",
              "eval_cost": "5.10",
              "prefix_cost": "10.48",
              "data_read_per_join": "816"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99303,99304,99305,99306,99307,99308,99309,99310,99311,99312,99319,99320,99321,99356,99357,99358,99359,99360,99361,99362,99363,99364,99365,99366,99367,99368,99374,99375,99376,99377,99378,99379,99380,99381,99382,99383,99384,99385,99386,99387,99388,99389,99390,99391,99392,99393,99394,99395))"
          }
        },
        {
          "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": 51,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "12.75",
              "eval_cost": "5.10",
              "prefix_cost": "28.33",
              "data_read_per_join": "816"
            },
            "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": 2,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "12.75",
              "eval_cost": "0.26",
              "prefix_cost": "46.18",
              "data_read_per_join": "6K"
            },
            "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')))"
          }
        }
      ]
    }
  }
}