Requesting CD-Key MoH on steam

Restart Steam?

Right click on MoH and there will be a "View CD-Key..." or something option. Click it and it will show it to you.

I thought this was going to be something else entirely...

On library click o MOH singleplayer, view cd-key. copy this cd-key to multiplayer

Use Humble bundle Origin key.

It happened to me with STALKER and Rome TW.
For STALKER I had to wait 2 weeks to get a CD key simply because they ran out of keys and had to request new ones.
It's something to be expected, especially now, due to the high amount of buyers & activations.
You will get one eventually.