SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff23a43a18dbd319a84e0b9eb4896b89c10d50e6fc0db93e69835aaba34f1ff4' 
  AND token = 'ohgzZ3JzV+FyooWwW5YLjGUAjMCt/8TmgWVKLA0S0w0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}