A victory will secure Wrexham's Football League status, providing there is a winner in the game between Macclesfield and Accrington Stanley.
"That's the ideal scenario. We're preparing ourselves to win two games but we'll see where we are at five o'clock on Saturday," said Carey.
"The players are ready for it, they know what's at stake here."
Wrexham have boosted their survival hopes with three consecutive wins, all without condeding a goal.
Their win over Shrewsbury on Tuesday took them three points clear of Boston, who occupy the last remaining relegation place, and a point above Accrington and Macclesfield.
But such is the precariousness of the situation at the bottom of League Two, certain results on Saturday could see Boston, Accrington, Macclesfield, Wrexham and Bury going into the final game of the season on the same number of points.
"We did ourselves a power of good on Tuesday by dragging other teams into the mix," said Carey.
"We're in a position now where we don't have to rely on other results going our way.
"The physical condition of the players is excellent and the message is that we just can't let up because we haven't done anything yet.
"We're still in the relegation dog-fight and we've got to try and go and win the game at Walsall on Saturday."
BBC