Perhaps this ambiguity is impossible in the German language but in English,
"Here is your Little Snitch 3 License Key" sounds like a three-seat license.
You might prefer to say "Here is your License Key for Little Snitch 3"
or "Here is your Little Snitch 3 single-user License Key" or similar.
Peace
--Devon
P.S. We're also less likely to capitalize words like "license key" in English.