Meta Box License Warning On Plugin Activation with MB Bundled

I am bundling Meta Box in a plugin. Forcing the end-user to have to access the wp-config.php to enter the license key would be a terrible user experience. I just want them to activate the plugin and not have to require any further action.

So I defined the constant in my plugin's main file like so:

if ( !defined( 'META_BOX_KEY' ) ) {
    define( 'META_BOX_KEY', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ123456' ); // Your Meta Box license key.
}

But that doesn't seem secure. I can obfuscate the key like so:

if ( ! defined( 'META_BOX_KEY' ) ) {
    $encoded_key = 'QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVoxMjM0NTY='; // Your base64-encoded Meta Box license key.
    $decoded_key = base64_decode( $encoded_key );
    define( 'META_BOX_KEY', $decoded_key );
}

But that's still not foolproof. Are there any other options?

Just to note: The encoded license key above is not my actual license key.

Yes, there needs to be a solution because otherwise, it's a bad user experience to require users that use the plugin I develop to have to purchase a Meta Box license and enter the license key in order to use the plugin.

I've seen plugins that bundle ACF that do not have this issue, so there should be a solution that can be added.