SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac43e3e81c57882cf90e75392c5f6e94905599477ef0dc3052b967169a9f09f' 
  AND token = 'IJ/PmDlgupOxF+Sd9EUlnF0fIyXU6aVPhjDUAezQtPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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