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 (
    99193, 99194, 99197, 99198, 99199, 99200, 
    99203, 99204, 99206, 99207, 99208, 
    99209, 99214, 99215, 99218, 99219, 
    99221, 99222, 99223, 99224, 99225, 
    99226, 99227, 99228, 99229, 99230, 
    99231, 99232, 99233, 99234
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00138

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "35.47"
    },
    "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": 62,
            "rows_produced_per_join": 62,
            "filtered": "100.00",
            "using_index": true,
            "cost_info": {
              "read_cost": "6.48",
              "eval_cost": "6.20",
              "prefix_cost": "12.68",
              "data_read_per_join": "992"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ],
            "attached_condition": "(`nuie_scalesta_net`.`cscart_products_categories`.`product_id` in (99193,99194,99197,99198,99199,99200,99203,99204,99206,99207,99208,99209,99214,99215,99218,99219,99221,99222,99223,99224,99225,99226,99227,99228,99229,99230,99231,99232,99233,99234))"
          }
        },
        {
          "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": 3,
            "filtered": "5.00",
            "cost_info": {
              "read_cost": "15.50",
              "eval_cost": "0.31",
              "prefix_cost": "34.38",
              "data_read_per_join": "8K"
            },
            "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": 3,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "0.78",
              "eval_cost": "0.31",
              "prefix_cost": "35.47",
              "data_read_per_join": "49"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "position"
            ]
          }
        }
      ]
    }
  }
}

Result

product_id category_ids position
99193 7349,7261M
99194 7320,7260M
99197 7320,7260M
99198 7349,7261M
99199 7349,7261M
99200 7320,7260M
99203 7258M
99204 7345,7347,7259M
99206 7258M
99207 7345,7347,7259M
99208 7349,7261M
99209 7320,7260M
99214 7262,7256M
99215 7262,7256M
99218 7258M
99219 7349,7261M
99221 7258M
99222 7258M
99223 7345,7347,7259M
99224 7345,7347,7259M
99225 7345,7347,7259M
99226 7345,7347,7259M
99227 7258M
99228 7345,7347,7259M
99229 7345,7347,7259M
99230 7320,7260M
99231 7320,7260M
99232 7320,7260M
99233 7349,7261M
99234 7262,7256M