Yes - you'd simply export the game as HTML5 and then upload the files to your site's public_html via FTP or by your hosts file manager (i.e cPanel)
You can then use any password protection you would use on a standard webpage; though most hosts will offer a simple though basic password protection feature. Alternatively you can just delist the page from search engines, hide it from crawlers, and give the page address a gibberish title and then share that with your audience.
If you're using C3 you can create a ephemeral preview that exists for as long as you maintain the preview with Remote Preview