The jury commissioner shall in the presence of one of the judges of the district court of the county, at such times as may be necessary, or as he may be ordered to do so by the district judge, select a number to be known as a key number. The selecting of a key number shall be done in a manner which will insure that the number selected is the result of chance. The key number shall be selected from among the numbers one to ten. The jury commissioner shall make a record of the manner in which the key number was selected, the name of the judge present, and the date and the hour of the selection, the same to be certified by the jury commissioner, and such records shall become a part of the public records of the county. The jury commissioner may use an electrical or mechanical system or device in carrying out his or her duties pursuant to this section.