“We have appealed (against the red card) and our appeal has been rejected,” Everton manager Moyes said.
“We were given no reason why it was rejected, but we immediately appealed against it.”
On Thursday, Everton shared a photo on their social media channels of Gueye and Keane wearing boxing gloves and embracing.
“It was over immediately,” Moyes told a media conference on Friday.
“It happened, that’s all. We moved forward very quickly and it was all sorted out inside the dressing room.”
“We want passion. We don’t always want it in the style that was shown 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 set to link 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 problem has ruled out captain Seamus Coleman, who was substituted in the first half at Old Trafford amid a season beset by injury concerns.
Asked if his team were weak in midfield, Moyes said: “Yeah, we are.
“Marilyn (Rohl)’s operation has lightened us up, so we’re a lot smaller but we’ve got other guys who can play out there – Charlie Alcaraz, Dwight McNeil, if we need to, too.
“I think those players can fill in there if needed.
“Merlin is probably not going to be back until the beginning of January and Idrissa’s suspension (and the upcoming Afcon participation) leaves us very behind in that area.”
Everton’s Premier League campaign continues at the Hill Dickinson Stadium on Saturday when they host Newcastle (17:30 GMT).
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