The key will not turn in the ignition the steering wheel is not locked.

I would be very surprised if a moped scooter had a 'Steering WHEEL'. In my day, they were called 'handlebars', and your part that failed is called the 'steering lock'. It is a generic Chinese scooter, so support is limited. If it is a combined ignition and steering lock, try turning it a full rotation one way or the other. Steering locks are normally a standalone device that is not part of the ignition, but can use the same key.

https://www.google.com/search?q=icebear+pmz150-17+scooter+steering+lock+removal

..

make sure steering wheel isn't resting too hard on the steering wheel lock, this could keep the key from turning

the ignition module (ignition switch on top of the steering column) normally doesn't get stuck.

things you can try:
steering wheel lock: (the pin gets a "burr" on it and locks everything up) wiggle steering wheel back and forth while trying to turn key.

transmission lock (parking on an incline will jam up the interlock)
push the shifter farther into park while trying to turn the key, or wiggle shifter

wiggle the steering wheel. this frees up the steering lock pawl, insided. all cars. if parked on a hill , against a curb 10x worse
read the operators guide, it covers this , in step one, driving.

your steering wheel lock is connected to ignition in column, pull hard on steering wheel in direction wheels are turned at the same time turn key, this should free them both up.

if your key is a transonder key wich has chip in it give it a couple of minutes to reset the code keep key in ignition and wait to see if it reads key or try another key and see if you have sameproblem make sure you unlock steering wheel disconnecting batteryfor posts might have reset car computer and cannot read ur key...

Try turning the steering wheel a bit when using the key. The steering wheel lock puts pressure on the lock cylinder to keep the wheel locked. If this pressure is high, it can keep you from using the key.

try this..turn the steering wheel as hard as you can until it locks(any direction)then put key in ignition and holding wheel over (anyway)turn key to start car.then when you park up turn wheel over 1/2 turn to park...should work...(toyota have an antitheft steering lock)the wheel will turn when steering lock is on.rather than break lock.please do not try to see if it works....only works once...and not in handbook...

Try turning the steering wheel (hard) right and left while trying to turn the key. Steering lock and Ignition lock kind of work in conjunction. Also make sure vehicle is fully in park.

either you have the wrong key,or try turning the steering wheel to the right all the way,then turn key,this usually happens when you park the vehicle and the wheels are turned,then the steering wheel locks hard