It's not a native USB keyboard but it does MIDI out and I use a MIDI-to-USB cable to connect it.
Minor latency going into and out of LMMS, enough to make live recording a bit... less-fun.
It's a Yamaha PSR 500m which I think is a sort of mass market keyboard.
I've had it for at least 10 years, probably more than that.
It handles MIDI patches oddly, which probably means it was made before GM got implemented (which unfortunately means I need to fiddle with events on channel 10 to make the drums line up right).
I think it's out of production by now... but if my experience is anything to go by, any MIDI-capable keyboard can connect to any MIDI-to-USB connector and interface with LMMS.
A note: You need to set MIDI out for each track individually, first the device, then the channel, and then velocity (if you want to override the velocity you've set for the notes in piano roll) and finally patch. Changing the channel will, if I remember correctly, *not* send a new patch change event, which means you'll be using grand piano (at best! Sometimes it won't even play the notes as is the case with Microsoft GM).
