MySQL table export – where clause that ignores empty rows Vs getting whole table, which would be faster?

I’m using MySQLWorkbench to export a large table from a database into a CSV. This is what the data in the table is like:

enter image description here

All the rows in the table have values for date, code1, string1, code2 and string2. But, the majority of a, b and c are empty. The command I’m using for getting this data right now is:

select * from table where code1 = '0001'; 

Given that a, b and c are empty for most rows, I could also do:

select * from table where code1 = '0001' and a <> ''; 

Which of the two do you think would export this table more quickly?

Edit: I don’t care about the rows where a, b and c are empty.