Hi Nilesh,
If understood you correctly, you did not flag the key fields in the Open Hub Destination (OHD) definition but in the data dictionary table definition (e.g. by double-clicing on the table name so that you get into an SE11 screen and then change the key fields). I don't think this is the right procedure.
You should define on tab page Destination that you use a Semantic Key.
Then on tab page Field Def. you checkmark the fields which make up the semantic key.
This way the table will show the respective fields as key fields.
If you will transport the OHD, only the OHD definition will be transported. The table will be generated in the target system (and has package $TMP).
Best regards,
Sander