Staking has a floating rate, which depends on the total number of tokens in the pool and the amount of tokens staked. Therefore, APR rate is calculated by the formula: Total Tokens Amount / Staked Amount * 100
No, staking does not have any locks ups for tokens. You can withdraw and deposit tokens at any time.
With the partial or complete withdrawal of tokens from the staking, your rewards are automatically claimed. This is done so that you do not need to spend additional fees on a separate transaction.