SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '06b12ec78d58ba1cf49f0e3ea415a31f0a69cda1737cd23684cc05657848e81a' 
  AND token = 'HtrCyKmK4HmZsEFYhZcROcoIS/5WixrISf/y1jZUbfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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