Let's first be clear, a password is not a token, and LCM is not vRA.
Can you explain what you want to do?
To get an access token from vRA, you need something like:
$api = "/csp/gateway/am/api/login?access_token"
$jsonbody = '
{
"username": "'+$user+'",
"password": "'+$pass+'",
"domain": "System Domain"
}
'
To get a password ID from the LCM locker, there are API's like:
/lcm/locker/api/v2/passwords
and
/lcm/locker/api/v2/passwords/{vmid}
But to access the Locker, you'll need to create a session to LCM first (log in api):
/lcm/authzn/api/login