We developed and implemented a multi-target multi-fidelity workflow to explore the chemical space of antiperovskite materials with general formula X(3)BA (X=Li, Na, Mg) and Pm-3m space group, searching for stable high-performance solid state electrolytes for all-solid state batteries. The workflow is based on the calculation of thermodynamic and kinetic properties, including phase and electrochemical stability, semiconducting behavior, and ionic diffusivity. To accelerate calculation of the kinetic properties, we use a surrogate model to predict the transition state structure during ionic diffusion. This reduces the calculation cost by more than one order of magnitude while keeping the mean error within 73 meV of the more accurate nudged elastic band method. This method identifies 14 materials that agree with the experimentally reported results as some of the best solid state electrolytes. Moreover, this approach is general and chemistry neutral, so can be applied to other battery chemistries and crystal prototypes.