Wordpress Database Crashing Website - Need An Urgent Fix

We have been having problems this week with our Wordpress website (www.latestfreestuff.co.uk). Everyday the website database goes down and we keep getting 'Internal Server Error'. It seems to happen at 8pm GMT everyday, but we're not sure if that's just a coincidence.

Our team have spoken to the hosting company and everytime we reboot the server it fixes the problem. The hosting company believe it's something to do with the Wordpress database causing high usage but we can't work out a problem and need an expert Wordpress database developer to help us with the problem.

Here's an extract of code that was extracted from the logs when the site went down, hopefully it can help debug the issue:

MySQL Processes (recorded at 2017-12-22 20:00:17):
| Id | User | Host | db | Command | Time | State | Info |
-----------------------------------------------------------------------------------------------
| 135185 | latestuk_old | localhost | latestuk_old | Query | 1128 | Sending data | DELETE a, b FROM wp_options a, wp_options b
WHERE a.option_name LIKE '\_transient\_%'
AND a.option_name NOT LIKE '\_transient\_timeout\_%'
AND b.option_name = CONCAT( '_transient_timeout_', SUBSTRING( a.option_name, 12 ) )
AND b.option_value < 1513971689 |
| 136308 | latestuk_old | localhost | latestuk_old | Query | 50 | updating | DELETE FROM `wp_options` WHERE `option_name` = '_transient_timeout_mashsb_limit_req' |
| 136394 | latestuk_old | localhost | latestuk_old | Query | 19 | updating | DELETE FROM `wp_options` WHERE `option_name` = '_transient_mashsb_limit_req' |
| 136421 | latestuk_old | localhost | latestuk_old | Query | 50 | Updating | UPDATE `wp_options` SET `option_value` = '1513972767.3758380413055419921875' WHERE `option_name` = '_transient_doing_cron' |
| 136424 | latestuk_old | localhost | latestuk_old | Query | 48 | Updating | UPDATE `wp_options` SET `option_value` = '1513972769.3426179885864257812500' WHERE `option_name` = '_transient_doing_cron' |
| 136429 | latestuk_old | localhost | latestuk_old | Query | 40 | Updating | UPDATE `wp_options` SET `option_value` = '1513972777.7542419433593750000000' WHERE `option_name` = '_transient_doing_cron' |
| 136430 | latestuk_old | localhost | latestuk_old | Query | 39 | Updating | UPDATE `wp_options` SET `option_value` = '1513972778.5874381065368652343750' WHERE `option_name` = '_transient_doing_cron' |
| 136431 | latestuk_old | localhost | latestuk_old | Query | 38 | Updating | UPDATE `wp_options` SET `option_value` = '1513972779.2866199016571044921875' WHERE `option_name` = '_transient_doing_cron' |
| 136432 | latestuk_old | localhost | latestuk_old | Query | 38 | Updating | UPDATE `wp_options` SET `option_value` = '1513972779.4597680568695068359375' WHERE `option_name` = '_transient_doing_cron' |
| 136433 | latestuk_old | localhost | latestuk_old | Query | 38 | Updating | UPDATE `wp_options` SET `option_value` = '1513972779.4930760860443115234375' WHERE `option_name` = '_transient_doing_cron' |
| 136437 | latestuk_old | localhost | latestuk_old | Query | 36 | Updating | UPDATE `wp_options` SET `option_value` = '1513972781.8112859725952148437500' WHERE `option_name` = '_transient_doing_cron' |
| 136441 | latestuk_old | localhost | latestuk_old | Query | 31 | Updating | UPDATE `wp_options` SET `option_value` = '1513972786.3412370681762695312500' WHERE `option_name` = '_transient_doing_cron' |
| 136443 | latestuk_old | localhost | latestuk_old | Query | 31 | Updating | UPDATE `wp_options` SET `option_value` = '1513972786.9130849838256835937500' WHERE `option_name` = '_transient_doing_cron' |
| 136444 | latestuk_old | localhost | latestuk_old | Query | 30 | Updating | UPDATE `wp_options` SET `option_value` = '1513972787.6311130523681640625000' WHERE `option_name` = '_transient_doing_cron' |
| 136446 | latestuk_old | localhost | latestuk_old | Query | 28 | Updating | UPDATE `wp_options` SET `option_value` = '1513972789.8794140815734863281250' WHERE `option_name` = '_transient_doing_cron' |


This is a very urgent issue that we're looking to fix in the next 24 hours if possible.

Please come back to me with what you think the problem and how you think you would fix it.