When you launch QuickLens for the first time, you will see this dialog alerting you about accessibility.
To use global hotkeys, you will have to enable accessibility for QuickLens. By clicking on “Open System Preferences”, you will be taken right into the Accessibility section where you can turn it on for QuickLens.
After enabling accessibility, you can configure global hotkeys for the tools in QuickLens » Preferences. Your tools can now be launched from anywhere using these global shortcuts.
Global hotkeys are the quickest way of bringing up your tools, anytime, anywhere!