Rugby Park defender Findlay was sent off eight minutes into Killie's Premiership clash with Ross County on Saturday for a foul on Ross Stewart.
Referee Colin Steven deemed the Scotland international to have denied the Staggies striker an obvious goal scoring opportunity and produced a straight red card.
The 10-man home side went on to win 3-1 but Killie boss Alex Dyer insisted afterwards he would appeal Findlay's dismissal, insisting the centre-back had got a touch on the ball
However, a fast-track tribunal hearing on Wednesday upheld the decision and Findlay will serve a one-match ban.
A statement on Kilmarnock's official website read: "A judicial panel has upheld the decision to show a red card to Stuart Findlay during the weekend's match with Ross County.
"The club challenged the decision to send the defender off after only eight minutes of Saturday's game with the Staggies.
"A fast-track tribunal hearing was held with the ruling that the card should stand and the defender will now miss our match with Hamilton on December 5."
Meanwhile, Holt has now been punished for his late lunge on Mason during Livi's 1-0 defeat to Saints at the Tony Macaroni Arena on Saturday.
Referee Willie Collum missed the incident midway through the second half and did not even give a foul against Holt, despite him catching Mason high up on the ankle.
Compliance officer Clare Whyte, however, decided the challenge did over step the line after reviewing the footage and charged Holt with an act of serious foul play after issuing a fast-track notice of complaint.
Livingston have accepted the charge and Holt will now sit out Saturday's Betfred Cup clash at home to Ayr and the Premiership visit of Dundee United the week after.