Will the payout for mining always be 0.00000064 BTC? Because that is what i just got.
As I write this, the block reward is 25 BTC and the difficulty is 37,392,766. Dividing gives .0000000668, which would be the pay per share at this moment for a pool that charged no fees and kept all transaction fees.
No, The payout is determined by the difficulty.
You can see how the difficulty has changed over time at this website.