The AbsoluteTime command returns the total number of seconds since January 1, 1900 in your time zone.

$\mathrm{with}\left(\mathrm{MmaTranslator}\left[\mathrm{Mma}\right]\right)\:$

$\mathrm{AbsoluteTime}\left(\right)$

$3.918320351\times {10}^9⟦s⟧$

$\mathrm{with}\left(\mathrm{MmaTranslator}\right)\:$

$\mathrm{FromMma}\left(\mathrm{`AbsoluteTime[]`}\,\mathrm{evaluate}\right)$

$3.918320351\times {10}^9⟦s⟧$