Código PHP:
$consm = "SELECT * FROM materias WHERE cvemateria=".$_GET[cvematerianueva]."";
$resm = $mysqli->query($consm);
$rm = $resm->fetch_array();
$cons = "SELECT * FROM materias WHERE cvemateria=".$_GET[cvemateriavieja]."";
$res = $mysqli->query($cons);
$r = $res->fetch_array();
if($rm[0]==$_GET['cvematerianueva'] && $r[0]==$_GET['cvemateriavieja'] ){
echo "pasa";
}else{
echo "no pasa";
}