In order to use them in your colony, such as for staking on Motions or to e eligible to receive Reward distributions (when that functionality goes live), they need to be Activated. Active tokens are tokens that have been deposited to a locking contract so that they can be locked in place any time you need to Stake. Active tokens will not be visible in your MetaMask wallet, but do not be alarmed, as long as they are not staked you can Deactivate your tokens and return them to your wallet at any time.