You can't send keys directly from a batch file, instead you can create a VB script to send the keys and call this script from a .bat file
Put the following code to a VB script, for example sendkeys.vbs (^ is Ctrl and % is Alt)
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.SendKeys "^%1"
Put the following code to a batch file, for example sendkeys.bat(required full path of the VB script if they are not in the same folder)
wscript "sendkey.vbs"
Finally, put sendkeys.bat to Windows startup folder.