SELECT 
  * 
FROM 
  cscart_abt__ut2_fly_menu_content 
WHERE 
  storefront_id = 3 
ORDER BY 
  position asc

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.35"
    },
    "ordering_operation": {
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "1.00"
      },
      "table": {
        "table_name": "cscart_abt__ut2_fly_menu_content",
        "access_type": "ALL",
        "rows_examined_per_scan": 1,
        "rows_produced_per_join": 1,
        "filtered": "100.00",
        "cost_info": {
          "read_cost": "0.25",
          "eval_cost": "0.10",
          "prefix_cost": "0.35",
          "data_read_per_join": "328"
        },
        "used_columns": [
          "item_id",
          "type",
          "storefront_id",
          "position",
          "content"
        ],
        "attached_condition": "(`s2cart`.`cscart_abt__ut2_fly_menu_content`.`storefront_id` = 3)"
      }
    }
  }
}