Solved: Thanks for the input and help on this one.
Here are the steps I took to fix.
Issue: Bought bike and key would not turn in lock. Bike sat for 3-4 years. Could hear tumblers moving when key inserted - but felt like it was wrong key when trying to turn - no movement at all.
Step 1A is to go get a few extra keys made. Thanks to JKJ Fz6 for this essential step!
1. Used pic tool to slide open key slot cover (see picture). Note: Slid pic tool to end of slot nearest front of scooter.
2. Inserted spray can tube (red in picture). Note: Slide tube in at end of slot closest to back of bike. When you think you are all the way in - jiggle and push and get it in further until you have bottomed out. It can go as deep as the key is long - so keep jiggling.
3. Once tube is fully seated in end, put paper towel or rag under lock. Its going to get messy.
4. Use Silicone or Teflon spray - NOT standard WD40 - locksmiths have the right spray - WD40 will attract dirt and cause more issues in future (according to lock smith experts I spoke with).
5. Spray. Spray. Spray. Flood the lock - make the liquid run out every where. What you are trying to do is get it to go out the back and in to the mechanism behind the lock. Look at this video to see what the lock looks like behind the cylinder - there is an actuation - this is what's sticking. Go to 5:11 of this video to see how far the key will turn, and whats happening at the end of the lock cylinder.
6. Now insert the key - you are going to have to turn it harder than you want to in a clockwise direction. If you can get it to move, don't try to turn it all the way - slow steps. Turn an 1/8", then back, then do it again and again until you work your way to being able to turn the key 90 degrees.
7. At 90 degrees, it is going to want to stop again - as the mechanism has a cam effect (see the video above again). So turn key back to 0, take it out, and spray spray spray. Get the tube all the way in there - and don't be shy.
8. Now do the same process to go from 90 degrees to 180 in small steps, turning it back after each slight push forward. Just keep working the key by turning it back and forth - and it will begin to slowly loosen. Spray again...
Note: if the youtube video link fails in future - search "vbb lock replacement" and go to 5:11 of the video so you can see what's happening inside as you are working the key.
Good luck - and make sure to have spare keys cut!
This worked for me with a VERY stiff lock that would not turn at all.
Slid the pick tool to the front of the slot
Slide the spray tube in until it is as deep as the length of the key - the issue is likely the mechanism at the back end of the cylinder
Work the key turning back and forth in small increments - achieving 90 degrees after many back and forth turns.