How to know which key got updated inside keyprefix is being watched

I am keeping a watch on prefix and then having a watcher handler script.
but is there a way to know which particular key got updated inside keyprefix directory while getting notification?

while firing command in result i get no output on my terminal and it starts waiting state and will trigger watcher handler command if watched key is getting updated.

Consul command is also not returning key details while starting a watch as shown in the figure.