MacBook Air does not respond to cursor clicks
First I would look if any of the running apps is doing that.

Press 3 keys together

alt + cmd + esc

In the new pop up window use the up or down arrow on your keybaord and when selected hit Enter key.

You can Force quit  anything showing in there.

If that did not help to restore normal function use again the keyboard to Restart.

To reboot your Mac instantly, hit Control-Command-Power/Eject.

Alternatively if you hold the power button for 2 seconds a screen should show up asking you what you want to do next.