Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_4 ( fastest_lap VARCHAR, winning_driver VARCHAR, date VARCHAR )

### Question ###
Who had the fastest lap of the race that Ayrton Senna won on 23 April?

### Accurate SQL ###

SELECT fastest_lap FROM table_name_4 WHERE winning_driver = "ayrton senna" AND date = "23 april"