Boco fired home a penalty in the 89th minute after former Stanley player Tom Aldred was adjudged to have pushed him in the area.
And then, in the fourth minute of added time, the midfielder got on the end of Sean McConville's cross to tap home the winner.
It was agony for Blackpool as they scored what they thought was a 81st-minute decider when substitute Michael Cain curled a 20-yard free-kick around the wall and into the bottom corner.
And goalkeeper Elliot Parish denied the Seasiders a second a minute later with a superb save from Brad Potts.
The game struggled to get going in the first half but livened up after the break with Kyle Vassell flashing a shot just wide for Blackpool while Parish denied Jamille Matt from distance.
McConville had an effort tipped away one-handedly by Sam Slocombe before the late drama.