Marsh's Memorandum of Insurance (MOI) is as one example of a digital certificate of insurance.

While the MOI is available to certificate holders 24/7, third parties would have to visit the MOI on a daily basis to confirm active coverage. 

For technical reasons, it's unlikely that links to MOI could be indexed to test feasibility of the index crawler idea.

Furthermore, attempts to do so would violate Marsh's terms of service:

"You may not link directly to the MOI ("deep link") or bring up or present the MOI or other content of this site within another web site ("frame"), except with the express prior written consent of Marsh."

Given that, it's probably not a good idea to link to any MOI examples.
GAPro System is currently an industry trailblazer that's as close as it gets to moving towards a real-time compliance "data portal." 

GAPro System
"Rewiring the Insurance Industry"
^ Click to learn more ^
Search queries for the term give examples 
of entities that currently use the MOI: