SELECT 
  COUNT(*) 
FROM 
  cscart_orders 
WHERE 
  company_id = 20 
  AND status = 'C' 
  AND is_parent_order = 'N'

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_orders",
      "access_type": "ALL",
      "possible_keys": ["status", "company_id"],
      "rows": 228,
      "filtered": 11.55355453,
      "attached_condition": "cscart_orders.company_id = 20 and cscart_orders.`status` = 'C' and cscart_orders.is_parent_order = 'N'"
    }
  }
}