ESXi is licensed per physical socket/processor, so you will have to get licenses for 2 sockets in this case.
Anyway, what do you want to achieve with the single host? Most advanced features are only available with multiple hosts, shared storage and vCenter Server managing the hosts.
If you only want to run that single host, but need a paid license to unlock the API in order to use VM based backup applications, a vSphere Essentials Kit may already be sufficient.
The differences btween the offered support services, please see On-Premise and Hosted Support Offerings: VMware
André