SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc1599864e65efd182050b59808cda27d467e11d9f75b81d0c5fb1fbb91f5c8d' 
  AND token = '/xKxoEwYw4Zd2+h7xNOUdaGZS1nbhjK8OjqVxtLKNYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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