^[

this must be replaced with:

\e

in the .inputrc file. So if you run ./key and say press Ctrl+Left_Arrow you will get this:

$ ./key raw
^[OC

Anyway now we know Ctrl+Left_Arrow is ^[OC 
so in your .inputrc you put:

"\eOC": forward-word

note s/\^[/\\e/g   Then do a bind -f .inputrc and it just works.