Logged in with a CloudSOC Administrator credentials, created multiple API Keys, and confirmed they were all listed in the Tenant.
However, logged on as the CloudSOC System Administrator, checked the Tenant > API Keys, and found the API Key list created by the other admin was not visible.
Working as designed; API keys are a specific to the credentials of the user who created them so it would be a violation of role-based access to allow another user to utilize those API Keys.
API Keys are specific to the Sys Admin that created them.
For more information see the document Creating an API key