The correct order of melting point of chlorides of alkali metal is:
For the same halide ion, the melting point of lithium halides are lower than those of the corresponding sodium halides and thereafter they decrease as we move down the group from Na to Cs.
The low melting point of LiCl (887 K) as compared to NaCl is probably because LiCl is covalent in nature and NaCl is ionic.
Hence the correct order is NaCl>KCl>CsCl>LiCl.