This Python script deletes keys adjacent to the playhead.
This script was created by a little bird who wishes to remain anonymous and not offer any further technical support. You are free to use it for whatever you want (MIT License)
put expander.py in your scripts folder (C:\Users\username\Documents\maya\scripts) and then assign this code to a hotkey or shelf button to trigger the expander script
[[This software is provided "AS IS" Without warranty of ANY kind express or implied. Author is not responsible for any damages or other liability]]