How can I turn off the keyboard on my Mac?

The shortcut for enabling/disabling the keyboard access doesn't work. I tried to change the shortcut to a different one, still doesn't work. It's ridiculous, I cannot clean my keyboard safely. On Windows you can easily turn off the keyboard by pressing shift 7 times in a row. The same for enabling it back. It's just so simple and useful, I wish this was available on a Mac as well. If you have any suggestions how to solve this problem, please help.

My operating system is MacOS 10.13.2 High Sierra

Thanks for advices.