SELECT 
  feature_id 
FROM 
  cscart_product_features 
WHERE 
  feature_type = 'E' 
  AND status = 'A'

Query time 0.00701

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "946.15"
    },
    "table": {
      "table_name": "cscart_product_features",
      "access_type": "ALL",
      "possible_keys": [
        "status"
      ],
      "rows_examined_per_scan": 9063,
      "rows_produced_per_join": 904,
      "filtered": "9.98",
      "cost_info": {
        "read_cost": "855.74",
        "eval_cost": "90.41",
        "prefix_cost": "946.15",
        "data_read_per_join": "388K"
      },
      "used_columns": [
        "feature_id",
        "feature_type",
        "status"
      ],
      "attached_condition": "((`s2cart`.`cscart_product_features`.`feature_type` = 'E') and (`s2cart`.`cscart_product_features`.`status` = 'A'))"
    }
  }
}