“We have appealed [against the red card] and our appeal was turned down,” Everton manager Moyes said.
“We haven’t been given any reason why it was turned down, but we did appeal it – immediately.”
On Thursday, Everton shared a photo of Gueye and Keane wearing boxing gloves and hugging on their social media channels.
“It was over immediately,” Moyes told a media conference on Friday.
“It was done, that was it. We moved on quite quickly and it was all sorted within the dressing room.
“We want passion. We don’t always want it in the style it showed up on Monday night but we certainly want that passion and commitment from all the players.”
Gueye has started every Premier League game for Everton this season and is due to join up with Senegal for the Africa Cup of Nations (Afcon) in December.
Moyes is also without German midfielder Merlin Rohl, who recently had hernia surgery, while a minor hamstring issue sidelines captain Seamus Coleman, who was substituted in the first half at Old Trafford amid a season beset by injury concerns.
When asked if his team were light in midfield, Moyes said: “Yes, we are.
“Merlin [Rohl] having an operation has made us light, so we are quite short but we have other people who can play in there – Charly Alcaraz, Dwight McNeil if we need to as well.
“I think those players can do the job in there, if required.
“Merlin probably isn’t going to be back until the start of January and Idrissa’s suspension [and forthcoming Afcon participation] leaves us pretty short in that area.”
Everton’s Premier League campaign continues at Hill Dickinson Stadium on Saturday, when they host Newcastle (17:30 GMT).