Changing the Yaris Hybrid key battery

Differently from most other car manufacturers, the Toyota car key can be opened without a screwdriver.

Start by pressing the "PUSH" label to extract the key.

 Pull it off completely

Right next to the extraction point, there's a small horizontal slot, just the size of the key tip.
Insert the key and rotate it.

The shell will open itself.

Now, play the same trick once more to remove the battery holder

and here it is the 3V CR2032 battery.