Prius key cannot unlock the door

I think a Toyota Dealership can cut a mechancal key that works on your car based on information in their data base.

 

So it seems you've already tried using your physical key and it will not unlock your car.

I was in a similar situation. I bought my 2010 Prius used with only 1 fob + key (which worked to unlock the car). But it's safer to have at least 2 fobs in case one is lost (or else it's expensive and a pain to reprogram a whole new set of fobs and keys from scratch). I bought an extra fob and programmed it myself using Techstream, but I went to the Toyota dealership to laser cut a duplicate of the physical key. They took my physical key and tried to make a duplicate FOUR times, and each one failed to unlock my car; at which point, they gave up. I magnified and compared all the duplicates against the original and I suspect the Toyota dealership's key cutting machine had a misalignment which caused all the failures.

So I went the eBay route and looked for a "2010 Prius key cut service" seller, which was ~$20 (if you care, it was this one: 2010-2015 10-15 Toyota Prius Door Key Lock Code Cut service 1 Key | eBay). In order for them to create the physical key for you, you send them a unique 5-digit code that's printed on the door lock cylinder (instead of sending the physical key or detailed photos). So I had to disassemble my door to remove the door lock cylinder to get that code. Just to be absolutely safe, I had it delivered to a different address than where my Prius is normally parked; it's probably much safer if you ask a close friend to purchase this key for you (so that both the name and address is not associated with your Prius in any public records).

 

You should try to squirt some anti-seize into the lock mechanism and work it. It may just be jammed from non-usage. I give mine a twist during my annual major maintenance to make sure everything works.

People lose their FOBs all the time. Since they're so expensive - people buy or trade FOBs and get them added to their car's electronic lock system - Never thinking about re-keying the manual over-ride key. So yes; it's a common practice - not necessary 'stolen'. Someone who has thought this through, would've laser-cut the back-up key at an additional cost. It may be worth it, if your always getting a dead battery and need to manually open the car door.

Just my two-cents......

FWIW; I would delete all the old FOBs from the car when electronically re-keying it (I believe the car can hold up to 4 FOBs) - So if the FOB was stolen rather than lost; someone doesn't drive off with the car. But that's just me......