Raymond L. Keller, 42, of 711 Pinewood Drive, district sales manager for Frito Lay Co., died Monday in Memorial Hospital, New York City, after a short illness. He was a Korean War veteran and a member of the Kanawha Two-Mile Gospel Tabernacle.  Survivors: wife, Phyllis; sons, Randy and Stanley at home; parents, Mr. and Mrs. Ray Keller of Orlando, FLa.; sister, Mrs Wilma Burns of Harrisburg, Pa., Mrs Agnus Petry of Pennsylvania.