Hide password in file with sed

I have a properties file that contains passwords, need to hide the passwords before the properties file can be distributed.

Input file:

prop1=1
prop2=2
password=123456 this is a test pw
prop3=3
password=789abc this is a prod pw

My sed command is:

sed 's/password=.*/password=xxx/g' < prop.txt > propnew.txt

prop1=1
prop2=2
password=xxx
prop3=3
password=xxx

As you can see I changed everything after password= to xxx, the ".*" did that.

What I want is:

password=xxx this is a test pw

Any suggestions on how to accomplish this with sed would be appreciated.
Thanks.

sed -e 's/password=[^ ]* /password=xxx /'

echo 'password=789abc this is a prod pw' | sed 's/password=[^ ][^ ]*\(.*\)/password=xxx\1/'
OR
echo 'password=789abc this is a prod pw' | sed -e 's/password=[^ ]*/password=xxx/'

Thank you quirkasaurus and vgersh99, the 3 methods suggested work fine.