SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84cec798ce111c08282759c9ad3095b56ed8341caf012739245859f3ed314c40' 
  AND token = '2DSve+TVnCjKxYAF9vZpd+bX5ieEiF93hgnJaOfViqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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