Can I use 2 agent pools in my azure pipelines?

This is not possible. There is a ticket on developer community asking for similar functionality but it is already closed.

There is another ticket Allow agent pools to contain Microsoft hosted and self-hosted agents which refer to similar case, it is open but MS is silent there.

Which benefits do you want to achieve?

Basically, you can use several agent pools in one build/release definition. You just split your definition into several jobs and assign the needed agent pool to the corresponding job.

If you want to dynamically assign different pools from one pipeline to do the same build steps, we can not do that (as Krzysztof mentioned).

You can do hacky thing and use multiple jobs/stages. Jobs/stages will use different pools. You just need to skip depending if it is release version. Note that pipeline skeleton is not tested.

variables:
  ${{ eq(variables['Build.SourceBranch'], 'release/*') }}:
    release_build: True

stages:
- stage: normal
  condition: eq(variables['release_build'], False)
  pool:
    vmImage: 'windows-latest'
  jobs:
    - job: Builds
      steps:
        - template: build.yaml

- stage: release
  condition: eq(variables['release_build'], True)
  pool: My-agent
  jobs:
    - job: Builds
      steps:
        - template: build.yaml