Try an alternate key.
I always keep a new spare hidden in the car just for such fun events.
Make sure if you have aftermarket floor mats that you try removing them when this happens to make sure that you are getting the clutch all of the way down to override the clutch safety switch.
Observe the volt meter when this occurs. Does the needle deflect when you go from run to start.
If it does not, then you are likely trapped in either the VATS protocol or the neutral / clutch switch protocol.
If it deflects then likely a starter issue.
If the clutch switch is the suspect, there is an override wiring procedure to update your 90.
Search the forum here and you will find it discussed.
If the key was the original culprit, likely still is until ruled out.
Keep us posted with your progress.
Marty