We derive a sufficient condition under which a version of Kolmogorov's 4/5 law can be rigorously proved for stationary solutions of the 3D stochastic Navier-Stokes equations. We name this condition 'weak anomalous dissipation condition'. A similar condition allows to prove flux scaling laws for the 2D stochastic Navier-Stokes equations, including a scaling law for the inverse cascade. We also...