Error Code: 2013. Lost connection to MySQL server during query with operator - OR

Question

I know there is 100+ posts about it, but there is a information about time out etc, not about query... MySQL Server: 5.7.17
MySQL Workbench: 6.3.8

Query:

SELECT transactionID, fromAccount,ToAccount, transactionDate, amount, type 
FROM accounttransactions WHERE toAccount = '12345' #OR fromAccount = '12345'

Respond: It works, but when I change my query and add(uncomment in this scenario) OR in WHERE statement then it Running for ~6s and looks like:

Error Code: 2013. Lost connection to MySQL server during query