There's an option called OMI_UNLOCK_FORCE in Metadata update procedures, you can use that option to unlock the locked table, here's a sample code,
But, I strongly recommend to take the Metadata Backup first before you execute this SAS Code,
Here's the sample code for SAS 9.4:
options metaserver='YOUR_METADATA_SERVER'
metaport=8561
metaprotocol='bridge'
metauser='sasadm@saspw'
metapass='PASSWORD_FOR_SASADM'
metarepository='Foundation'
;
options ls=max ps=max noquotelenmax ;
proc metadata
in='<GetMetadata>
<Metadata>
<PhysicalTable Id="INSERT_YOUR_PHYSICAL_TABLE's_ID_HERE" />
</Metadata>
<NS>SAS</NS>
<Flags>262144</Flags>
<Options>
</Options>
</GetMetadata>'
verbose;
run;
Make sure you change metaserver, metapass and most importantly "PhysicalTable Id" value in this code,
You can get PhysicalTable's Id from you error message itself:

After running this code, the Table should be unlocked.
For your reference: https://documentation.sas.com/?docsetId=omaref&docsetTarget=n0jz5u1b73d8czn1wil2biqcusr5.htm&docsetV...