In re your query . . . as he was born in 1837, that would have made him 17 at the time of the Crimean War, and he would probably not have had enough time in the service at that age to have risen to the rank of Farrier Major.
There was no one named Keyworth in the Light Brigade during the Crimean War. I am about 2/3 done on a book on the men of the Heavy Brigade in the Crimean War, and there was only one Keyworth serving with them that I have found to date . . . 1322 Pte Samuel Keyworth, 6th Dragoons. He was born at St Luke's; enlisted 13 May 1854; prior occupation: toolmaker. He embarked for the Crimea, but fell sick and was left at Scutari from June 1855 through September 1855. He volunteered to the 7th Dragoon Guards on 1 September 1857.