Solution 1:

After a while, I've noticed that all shortcuts work in Finder. Here are my steps, how I fixed the problem:

  1. Try to launch finder, by killing rest of the apps via "force quit apps" menu (Command+Alt+Esc)
  2. Go to utilities folder (Shift+Command+U)
  3. Use arrows to select Terminal
  4. Open terminal (Command+Down Arrow)
  5. Issue command sudo shutdhown -r now. I decided to use -r flag to reboot my mac, in case power button is dead and I won't be able to load it.

Now everything works fine. It was just a software bug.