Electromagnetic form factor, especially its asymptotic behavior for large momentum transfer (Q²), of kaon provides crucial insight into the partonic structure of a Nambu-Goldstone boson in strong interaction. Studies of the electromagnetic form factor of kaon up to Q² ∼ 6 GeV² are underway at the ongoing JLab12 experiment, and its measurements in an extended range of Q² ∼ 9 – 30 GeV² are planned at the future Electron Ion Collider (EIC). For the first time, we will present results for the kaon electromagnetic form factor in the range of Q² ∼ 2 – 10 GeV² from state-of-the-art lattice QCD calculations carried out using physical values of up, down and strange quark masses. These results will provide benchmark QCD predictions for model-based studies and the experimental measurements, in particular at the boundaries between the JLab12 and the EIC.