First, your expression for K is wrong. What are the exponents of [H+] and [O2]?
Having got that right, calculate the reaction quotient Q, using the same expression as for K, but inserting the actual concentrations of the species.
If Q<K, the tendency is for the reaction to proceed in the forward direction, increasing Q until Q=K.
If Q>K, the tendency is for the reaction to proceed in the reverse direction.