SELECT 
  order_id 
FROM 
  cscart_orders 
WHERE 
  order_confirmation = 0 
  AND status = 'E' 
  AND order_status_update_timestamp > 0

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "4.80"
    },
    "table": {
      "table_name": "cscart_orders",
      "access_type": "ref",
      "possible_keys": [
        "status"
      ],
      "key": "status",
      "used_key_parts": [
        "status"
      ],
      "key_length": "3",
      "ref": [
        "const"
      ],
      "rows_examined_per_scan": 4,
      "rows_produced_per_join": 0,
      "filtered": "3.33",
      "cost_info": {
        "read_cost": "4.00",
        "eval_cost": "0.03",
        "prefix_cost": "4.80",
        "data_read_per_join": "1K"
      },
      "used_columns": [
        "order_id",
        "status",
        "order_status_update_timestamp",
        "order_confirmation"
      ],
      "attached_condition": "((`webmarco`.`cscart_orders`.`order_confirmation` = 0) and (`webmarco`.`cscart_orders`.`order_status_update_timestamp` > 0))"
    }
  }
}