Mysql – Deadlock on inserts to a single table with a single key. (Mysql)

I have a simple game server.
One of the requirement i received was to handle a single request for a single player at a time. so in order to achieve that i decided to create a lock table:

CREATE TABLE `GameRoundLock` (`theKey` varchar(255) NOT NULL,
PRIMARY KEY (`theKey`))
ENGINE=InnoDB DEFAULT CHARSET=utf8;

Before I handle any request from any player I am inserting a row into that table like so:

// save and flush == acquiring the lock
GameRoundLock lock = this.gameRoundLockRepository.saveAndFlush(somePlayerKey);

   /** Play busniess logic here...  **/

// deleting == releasing the lock
this.gameRoundLockRepository.delete(lock); 

This actually works.

In the following scenario the whole system works as expected:

1) PlayerA plays, therefore a new lock is inserted.

2) handling playerA request… (takes 30 seconds)

3) While 2) is still executing, PlayerA plays again – This ofcourse resulting in trying to create a lock for him, and the thread now awaits till 2) completes.

4) thread of 2) completes

5) thread of 3) now continuing

6) DONE, playerA total played rounds == 2.

****Pay attention that the id (playerKey) is identical.****

The problem arises when the playerA tries another play request while the handling of the first thread still occurs. here is the scenario that resulting in a weird deadlock:

1) PlayerA plays, therefore a new lock is inserted.

2) handling playerA request… (takes 30 seconds)

3) While 2) is still executing, PlayerA plays again – This ofcourse resulting in trying to create a lock for him, and the thread now awaits till 2) completes.

4) While 2) is still executing and 3) is still waiting, PlayerA plays again – This ofcourse resulting in trying to create a lock for him, and the thread now awaits till 2)/3) completes.

5) thread of 2) completes

6) ERROR – a deadlock is thrown!!!!!

Here is the deadlock info:

------------------------
LATEST DETECTED DEADLOCK
------------------------
2016-11-23 17:05:26 0x1d98
*** (1) TRANSACTION:
TRANSACTION 5493356, ACTIVE 8 sec inserting
mysql tables in use 1, locked 1
LOCK WAIT 3 lock struct(s), heap size 1136, 2 row lock(s)
MySQL thread id 5191, OS thread handle 5152, query id 15582091 localhost    127.0.0.1 root update
insert into GameRoundLock (theKey) values ('1,1,1,64')
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 4865 page no 3 n bits 72 index PRIMARY of table      `game_server`.`gameroundlock` trx id 5493356 lock_mode X locks rec but not gap    waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 3; compact format; info bits 32
 0: len 8; hex 312c312c312c3634; asc 1,1,1,64;;
 1: len 6; hex 00000053d266; asc    S f;;
 2: len 7; hex 790000030903d1; asc y      ;;

*** (2) TRANSACTION:
TRANSACTION 5493355, ACTIVE 12 sec inserting, thread declared inside InnoDB    1
mysql tables in use 1, locked 1
3 lock struct(s), heap size 1136, 2 row lock(s)
MySQL thread id 5193, OS thread handle 7576, query id 15582083 localhost    127.0.0.1 root update
insert into GameRoundLock (theKey) values ('1,1,1,64')
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 4865 page no 3 n bits 72 index PRIMARY of table     `game_server`.`gameroundlock` trx id 5493355 lock mode S
Record lock, heap no 2 PHYSICAL RECORD: n_fields 3; compact format; info     bits 32
 0: len 8; hex 312c312c312c3634; asc 1,1,1,64;;
 1: len 6; hex 00000053d266; asc    S f;;
 2: len 7; hex 790000030903d1; asc y      ;;

*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 4865 page no 3 n bits 72 index PRIMARY of table    `game_server`.`gameroundlock` trx id 5493355 lock_mode X locks rec but not gap    waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 3; compact format; info    bits 32
 0: len 8; hex 312c312c312c3634; asc 1,1,1,64;;
 1: len 6; hex 00000053d266; asc    S f;;
 2: len 7; hex 790000030903d1; asc y      ;;

*** WE ROLL BACK TRANSACTION (2)

It seems like two "close\near" inserts for the locks of the 2nd and 3rd play requests causes this. why a deadlock and how to mitigate it?