Code:
alias hadd {
  if (-*u* iswm $1) && (($hget($2) != $null) || (-*m* iswm $1)) && ($3 != $null) && (-*r* iswm $1) {
    var %t = $+(.timer,_hexp,$ticks)
    %t -hi 0 500 _hexp $2 $3 %t
    hadd -m hexpire $+($2,$3) $4-
  }
  hadd $1-
}
alias -l _hexp {
  if ($hget($1,$2) != $null) return
  $3 off
  hadd hexpire table $1
  hadd hexpire item $2
  .signal -n hexpire $hget(hexpire,$+($1,$2))
}
alias table return $hget(hexpire,table)
alias item return $hget(hexpire,item)

; Example code to test it

on *:signal:hexpire: {
  echo -a table: $table
  echo -a item: $item
  echo -a value: $1-
}


This will just start a timer (resulting in a signal after unset) if you use hadd -ru60 f.e.