The order of melting point of chlorides of alkali metals is:

The amount of energy needed to split one mole of a solid ionic compound into its gaseous ions is known as lattice energy. Evidently, the melting point of the alkali metals halide is higher and its solubility in water is lower the higher the lattice energy.
The melting points of lithium halides are lower than those of the analogous sodium halides for the identical halide ion, and they then get lower as we travel from $\mathrm{Na}$ to $\mathrm{Cs}$ in the group.
Because $\mathrm{LiCl}$ is covalent in nature and $\mathrm{NaCl}$ is ionic, LiCl has a lower melting point (887 K) than $\mathrm{NaCl}$.
Therefore, the proper sequence is $\mathrm{NaCl}>\mathrm{KCl}>\mathrm{CsCl}>\mathrm{LiCl}$ .