There is no way to query based on this criteria. There are also no reports that would provide this information. You can check on a record by record basis by following the steps below.
  1. In Luminate Online go to Constituent 360 > Constituents
  2. Search for a record
  3. Click View for that record
  4. Click on the Interactions tab
  5. Click Emails Sent
All emails sent from your organization to the constituent will be listed here. Autoresponders will not be included in this list. If the constituent has never received an email from the organization 'no emails have been sent to this constituent.' will be displayed in the list.