SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f728b6bff97a496d91fc70cb9761cd3d783851f78cebbaad83363fe9ad1cba16' 
  AND token = 'uRjp9vxgY/aqdb4Xo+RKHFe5nCQPi/2LNPDU3lD9Itw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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