A delete with a future timestamp doesn't execute in the future, it is applied to the timeline immediately. Which is the same as all other tx operations. I think what you should consider instead is to make the if-else logic happen at query time and model your own "delete" concept as a new entity or attribute. Just to be sure though, can you say more about the use-case?

With this new knowledge it seems what I wanted was [[:crux.tx/delete :mykey] [:crux.tx/put mydoc (now) (new-deletion-time)]]