Maybe:
(defun c:test (/ usrexplmode ent ss)
(if (setq ss (ssget "_X" (list (cons 0 "INSERT") (cons 410 (getvar 'CTAB)))))
(progn
(setq usrexplmode (getvar "explmode"))
(setvar "explmode" 1)
(mapcar '(lambda(x)(command "._explode" x)) (mapcar 'cadr (ssnamex ss)))
(setvar "explmode" usrexplmode)
)
)
(princ)
)