Conection string class mysql C#

Question

I have more then 50000 records in table

Using connection sting in class
Time I spent now is more then 30 seconds, default value.
Need to setup conection life time or Conection time out
Need help

string server = ConfigurationManager.AppSettings["server"].ToString();
string username = ConfigurationManager.AppSettings["username"].ToString();
string password = ConfigurationManager.AppSettings["password"].ToString();
string database = ConfigurationManager.AppSettings["database"].ToString();
// string conection = ConfigurationManager.AppSettings["connection time"].ToString();
conn = new MySqlConnection(@"server=" + server + ";userid=" + username + ";"
            + "password=" + password + ";database=" + database);

OR

conn = new MySqlConnection("Data Source='192.168.1.135';Port=3306;Database='prijavnica_app';UID='prijavnica';PWD='prijavnica'; Connect Timeout=120;");