The Difference with Proof-of-Stake
Don't confuse this mechanism with Proof of Stake (PoS). You don't have to be online or run a full node (native mode) to receive the reward. Komodo's UTXOs accrue rewards based on UTXO value and locktime.
Also, note that rewards do not apply to funds held on most exchanges where you do not own the private key! This means that if you want to claim your 5% reward, you should transfer your KMD from an exchange wallet to your Guarda Wallet.