Does US Federal Law explicitly prohibit election misinformation?
Neither 18 U.S. Code CHAPTER 29—ELECTIONS AND POLITICAL ACTIVITIES nor 52 U.S. Code Subtitle I—Voting Rights contain any "explicit" prohibitions on election misinformation. Consequently, any "speech" containing misinformation must be prosecuted under other laws.
The complaint states a violation of "Tile 18, United States Code, Section 241", which is defined in 18 U.S. Code § 241 as "Conspiracy against rights".
If two or more persons conspire to injure, oppress, threaten, or intimidate any person in any State, Territory, Commonwealth, Possession, or District in the free exercise or enjoyment of any right or privilege secured to him by the Constitution or laws of the United States, or because of his having so exercised the same; ...
Conspiracy to "injure" a right to vote by misleading a voter would seem to qualify as a violation of US law.
However, H.R.1 - For the People Act of 2019 (116th Congress), had it passed, would have amended 18 U.S. Code § 594 - Intimidation of voters to make certain "deceptive acts", related to federal elections, unlawful.
These deceptive acts include "by means of written, electronic, or telephonic communications, to communicate or cause to be communicated information" that "has the intent to mislead voters, or the intent to impede or prevent another person from exercising the right to vote in an election" regarding "the time or place of holding any election" or "the qualifications for or restrictions on voter eligibility for any such election".
H.R.3281 - Deceptive Practices and Voter Intimidation Prevention Act of 2019 and S.1834 - Deceptive Practices and Voter Intimidation Prevention Act of 2019 were introduced in the House and Senate, respectively, to apply those same deceptive acts to 52 U.S. Code § 10101 - Voting rights subsection (b).
Note that 18 U.S. Code § 594 and 52 U.S. Code § 10101(b) have similar goals with regard to voting.
Since Democrats, having introduced the "deceptive acts" legislation, one might expect them to reintroduce similar legislation.