Well, tram journey isn’t counted as part of rail but as flat bus fare of £1.65, so you can’t find the fare directly but rather as a composite of two fares, one of National Rail and one of tram.
According to the rail map and service pattern I believe there are two choices of trains from Ewell East to connect to the tram, one more frequent to West Croydon (train bound for London Bridge via Sutton) which is in zone 5, one less frequent but that of shorter journey to Mitcham Junction (train bound for Victoria) which is in zone 4.
So the train fares touching in Ewell East are as follows:
Mon-Fri 0630-0930 and 1600-1900
To West Croydon: £3.00
To Mitcham Junction: £3.40
All other times
To West Croydon: £2.60
To Mitcham Junction: £2.80
So the total fare ranges from £4.25 to £5.25