I have a Storm watch called "Navigator" that has an LED included. It has no usefull output but enough to get the key into the keyhole if in darkness. Compareable to those cheap cheap LED keychain lights.
The following picture was taken "in action" :naughty: while a friend of mine hid in an all black corridor within the ruins of a 300 years old french gigantic fortress (Mont Royal) here in germany. The picture was taken by him standing about 12m away from me.