Keyboard Shortcuts to Lock Your Mac

At work, I have this principle that whenever you leave your workstation unattended even for just a few minutes, you should lock it. Ever since I started using Mac OS, one question that was left unanswered was how do I lock my machine using just keyboard shortcuts? Things would be so much easier if I can do that instead of having to click twice.

I'm not sure if things changed or I was just inattentive but I decided to search for a solution again. Google sent me to two sites that provided two keyboard shortcuts for MacBooks manufactured after 2011:

1. Ctrl+Shift+Power
2. Cmd+Option+Power

I tried them both and they worked. I closed the tab where the site was loaded and tried again. Nothing. What madness is this? Was it a JS script or something? I tried again. Still nothing. I tried again for the third time button by button and slowly this time. It worked. Slowly but surely seems to be the key. Well, that's one more problem solved.