Comment by rrebelo

Sorry for the shameless plug, but for those without an Apple Watch I've made a program [0] that implements the Unlock Mac with Bluetooth for any other device, including Android phones, Android Wear or Tizen watches or even some ear plugs.

[0] https://www.gadgetish.com/osx.html

Edit:

However, the Windows version works only with Android phones: https://www.gadgetish.com