Titanfall CD product key code

Where can I get a replacement game key? The game is a 50gb download, I can get a "physical disc" to install, I don't have the time or bandwidth to download it. (the cd key has already been used) All I need is a key to install the game... is there a difference between a "Physical key" & a "Download key"? Would there be issues when installing game? What would be the proper way to do this? Thanks