What you are attempting to do is imply as much information as possible. You do not need to do this all in one step.
First, trim the fat.
"...for your business?" is implied and so can be dropped.
"Are you looking for..." is not conveying information. This is something that looks good in a headline but we are attempting to get as much information into the smallest space possible.
"We are a..." is again something we can strongly imply. "We are a full-service studio that can do everything for you" can be trimmed to "our full-service studio can do everything for you".
What that leaves us with is:
There's no marketing more powerful than an explainer video; our full-service studio can do everything for you.
That can be said with fewer words if you are prepared to be informal.
No marketing is more powerful than an explainer video; our full-service studio has you covered.
personally, I'd go for a bit of swapped out word choice that expresses the implied "we are the best" from the original text. We end up with:
No marketing is as effective as our studio's full-service explainer videos.
The essential information remains, secondary information is implied. Surplus words have been cut.
If every character counts:
No marketing works like our studio's full-service explainer videos.