The Newcastle forward appeared as a 57th-minute substitute in Abu Dhabi, having been an unused substitute in his side's opening game of the tournament - a 3-2 success over Turkmenistan.
Muto will hope to be involved again in Thursday's final group game against Uzbekistan.
Ki Sung-yueng was an unused substitute in Korea Republic's 1-0 win over Kyrgyzstan on Friday, having picked up an injury in their opening game against the Philippines.
Korea Republic's final group game is against China on Wednesday.