SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '125a72f5e50b668905096af429961ba3e0ea6914aba94ab4dd8ce760b878cb54' 
  AND token = 'qoOTOF7HcUBQx5VX1AUg+IEOrIcojLaJF8/3g9uiBw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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