SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbaa8f0d4121ea6377229e01e991b20ccddae7f089a01f93c47d1a4c2eedfc67' 
  AND token = 'xX/PX5VF9z+B5nAzH9AmncmQhIhNMnqW7UdaKDVaDBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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