Hi there,
We no longer use CD keys except for legacy purposes. If you no longer wish to use Steam, though, that's very very simple: simply take the files from the "ai war fleet command" folder in your Steam apps folder, and move them wherever. You won't ever need a CD key with them, or to use steam, or anything like that. You can easily use the in-game updater.
On our own website, we sell the same version with no CD keys now, too. So literally the demo with the CD keys is only for two purposes: people who have CD keys from somewhere in the past but not the new keyless versions; and for demo purposes.
Hope that helps!