There’s two separate but related issues you need Solved for this.
One is putting ticks on the timeline at arbitrary BPM (or whatever else) intervals.
The current “workaround” method for getting something like that is to create a CSV file with the timestamps of where you want marks, then import them as guides. It’s a bit messy if you’re only using a few of them, but things will snap to them 
This will work so long as your beat interval is a multiple of the frame duration. There’s some discussion on that here: Beat detection, change video on audio beat
The other one is aligning the actual beats in your audio file to those marks - since you can only align the start of your audio clip to a frame boundary. (For 30fps video, having your beats hit with an error of up to 15ms off cue is going to be notably jarring). There’s some discussion about that here: Feedback from a beginner, climbing the learning curve
And there’s a third issue where if the beats in your audio are generated by a human playing rather than a sequencer, then over a long enough interval even a tight player is going to deviate from your perfectly marked timing … so now we need a beat detection filter, and arbitrarily spaced marks, too
But all of these would be lovely things to have on the roadmap and to have someone with the right combination of itch and skill working on. But it might also need work in mlt to make all of it possible.