SELECT 
  filter_id, 
  feature_id 
FROM 
  cscart_product_filters 
WHERE 
  status = 'A'

Query time 0.00008

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_filters",
      "access_type": "system",
      "rows": 1,
      "filtered": 100
    }
  }
}