SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd38944ac3e405e8eb226f542e2e7a6ab612fb3564f906d938373ef264c40224c' 
  AND token = 'faxQaYMFWU9V433kwmHZUMpoFjVLcZq7CG1PGhb7qDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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