;
You dont need define variable here. Also you should use "=>" instead of "=" as follow.

incoming_token => params->{token}

Ok, but now how can I access the value of incoming_token? Is it now a scalar?

How can I use it to do for example

if (incoming_token eq 'blahblablah) { #then do something }

To me if it doesn't have $ in front of it I don't know how to handle it.