Create text file "email.txt" and put your email into it.
Next create another text file and paste following code into it:
Set wshShell = CreateObject("WScript.Shell")
WshShell.Run ("cmd.exe /C clip < email.txt"), 0, true
Rename this file "email.vbs". This vbscript file (email.vbs) won't allow to assign shortcut key, so create a shortcut of the "email.vbs" and then you can assign shortcut key to it.
Every time shortcut key is pressed, content from email.txt (your email address) is being copied to clipboard and you can paste it easily.