Once you have done that buy another key and get it coded by your dealer
as, if you loose your one key then you have to replace large chunks of
the car security system (you need one working key to programme a new
key) and that costs an eye watering amount in any currency.

Also, to check how many keys are coded to the security system press the
boot/trunk release button on the key whilst it is in the ignition and
the engine running, the SID will come up with how many remotes (the
active radio bit that locks/unlocks the doors) and transponders (the
passive bit talks to the security system when the key is in the
ignition).

Andy