Release the key when you see the login window and log in.

To boot into Safe mode, turn off (or restart) your Mac, and then press Shift as it boots. It also scans your hard drive for issues at boot, which might help fix the problem. Safe mode starts your Mac with the bare minimum number of drivers required to run the system.

If the problem is easily replicable, you can try booting your Mac in Safe mode to see if the issue persists. If you appear to have resolved the problem, consider also updating any software related to that peripheral. Unplug all external peripherals, including mice, keyboards, USB audio interfaces, storage devices, and webcams, and then test for the issue again. To rule this out, make sure your Mac is running the latest version of macOS, and that you’ve installed any required firmware updates under System Preferences > Software Updates. If your freezing issue is a regular occurrence, it could be caused by a hardware fault.

Is Your Mac Freezing During or Shortly After Boot?

How to turn on macbook in safe mode