Unfortunately, if a video has not yet been claimed, we must wait for YouTube to do this automatically - we cannot currently claim a video manually.
Once your beat is submitted for Content ID, YouTube will scan all newly uploaded videos for possible matches, as well as retroactively scanning existing videos. As you can imagine, this takes a long time. Videos uploaded before your submission can take at least 6 months to be matched, whilst new videos can (but won't always) be claimed as soon as they're uploaded.
Content ID is available to Platinum members only. If you have a free account, you can upgrade here.