A search for the decay ${K}_{S}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ is performed using proton-proton collision data, corresponding to an integrated luminosity of $5.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ and collected with the LHCb experiment during 2016, 2017, and 2018 at a center-of-mass energy of 13 TeV. The observed signal yield is consistent with zero, yielding an upper limit of $\mathcal{B}({K}_{S}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})<2.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ at 90% C.L.. The limit reduces to $\mathcal{B}({K}_{S}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})<2.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ at 90% C.L. once combined with the result from data taken in 2011 and 2012.