No skill on the skill tree reduces the cooldown of any abilities; they only improve certain stats.
And as far as I know, no Doff has an Active Power that reduces the cooldown on Jam Sensors/Scramble Sensors directly. The closest thing you've got is slotting the Technican, which on use of Auxiliary to Battery, reduces the cooldown on all Boff abilities by a small amount.
Was named Trek17, but still an author.
Been playing STO since Open Beta, and have never regarded anything as worse than 'meh'.