Before macOS 10.13 High Sierra, users could turn on the Keychain Access menubar item and have quick access to lock screen or keychain directly from the menubar.
This has been removed since macOS 10.13 High Sierra and replaced with a new fuss-free and quicker method to lock screen whenever we need to walk away from our macs with the assurance that prying eyes/hands are shielded from our macs.
Previously a secret lock screen trick could be enabled in the Keychain Access utility preferences, simply by checking the “Show Status in Menu Bar” option in the General tab.
This would turn on a Keychain Access menubar item that provided amongst others, the option to lock screen at a click of a mouse.
In macOS 10.13 High Sierra, users can now choose to either click on the Apple logo menu and proceed to click the “Lock Screen” menu item or use the keyboard shortcut CTRL + CMD + Q.