SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '513db7d28d916d9291f89960941959c7ba42738ed6839e2458d7edbb1c0a43ca' 
  AND token = 'wiBccaJZ8bDjHn+lPspTUCi8Yrbj8jX+IvJLZo2qlzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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