We propose a possible explanation for the recent claim of an excess at 3.5 keV in the x-ray spectrum within a minimal extension of the standard model that explains dark matter and baryon abundance of the Universe. The dark matter mass in this model is $\mathcal{O}(\text{GeV})$ and its relic density has a nonthermal origin. The model includes two colored scalars of $\mathcal{O}(\text{TeV})$ mass ($X_{1,2}$), and two singlet fermions that are almost degenerate in mass with the proton ($N_{1,2}$). The heavier fermion $N_2$ undergoes radiative decay to the lighter one $N_1$ that is absolutely stable. Radiative decay with a lifetime $\sim {10}^{23}$ seconds can account for the claimed 3.5 keV line, which requires couplings $\sim {10}^{-3}–{10}^{-1}$ between $X_{1,2}$, $N_{1,2}$ and the up-type quarks. The model also gives rise to potentially detectable monojet, dijet, and monotop signals at the LHC.

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