A very high energy (VHE) γ-radiation was detected from a flat spectrum radio quasar (FSRQ) 4C 21.35 (PKS1222+21) by MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes on June 17 th 2010. 4C 21.35 is only the 3 rd FSRQ detected in VHE γ-rays. With its hard spectrum (Γ = 2.72+/-0.34) with no apparent cut-off at energies below 130 GeV and an extremely fast variation of flux (doubling in 8.6+1.1 -0.9 minutes), this detection poses a challenge to existing models of VHE γ-radiation from FSRQs. The most important results of observations performed by MAGIC telescopes are presented here, as well as some possible explanations of those results.