SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66123801c4d4e484a95500aa222ef9cca1a6c10b081e959264917d44e0021a97' 
  AND token = 'b/SMAwXCdj6ev+lunPZtQmHJK7ktcc8J8NBiexbCPC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}