fix: slow connection request creation after 300K requests

[ankita-p17]

Preliminary Checks

• I have read the contributions guide contibution guide and agree to it
• I have searched existing issues and pull requests to avoid duplicates.
• I'm willing to create a PR for this feature. (if applicable).

🧪 Steps to Reproduce

After processing over 300,000+ records, we noticed a significant slowdown in the query response time when generating an OOB Issuance and connection invitation.
We noticed that in repository was querying all data and filtering later on. Creating this bug to fix this issue while using on scale.

✅ Expected Behavior

Use API - /credentials/oob/offer
Expected - Returns credential offer

❌ Current Behavior

Current Behaviour - 408 Request Timeout OR 500 Internal Server Error

📌 Affected Version/Commit

No response

💻 Environment

• Local development
• Production
• CI/CD
• Other

🧾 Relevant Logs, Screenshots, or Stack Traces

No response