How do I preview a Live Photo using the keyboard in Photos.app?

The ability to playback Live Photos in Photos.app is a nuisance at best. So far I've only been able to play them by hovering over them with my mouse, either over the 'Live' tag in the bottom left hand side of a full view photo, or hovering over the photo in the gallery view (which plays without sound).

Is there a keyboard shortcut that can be used to start the preview in one or both views?

Spacebar doesn't work, as that switches between full size/edit mode, and gallery mode. There is no shortcut that I've found in the app's menus.

I don't know how long this have been the case, but now you can use option ⌥ + Space combination to start playback on a Live Photo or video (works on Catalina)

If you have a 2016 or 2017 MacBook Pro w/ Touchbar there is a small icon which plays the Live Photo.

Unfortunately I haven't found a solution for MacBook users w/o Touchbar so far...