The β-decay half-life of ⁷⁰Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated ⁷⁰Kr ions were produced by 1 GeV proton-induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of ⁶⁸Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 10⁶ g/cm³.