You are missing a few \r\n and the length you are giving to your AT+CIPSEND is incorrect.
Try sending this instead:
To send \r\n just hit Enter. Make sure that "Both NL & CR" is selected in your serial monitor. At the end, yes you hit Enter twice.
Here I am sending the value 2.
Here how I get the 43 length: You take the size of your GET (we have 49) and you subtract 1 for each \r or \n. Because they are just one character. So we have 49 - 6 = 43.
Please, make sure to try to send a value directly from the URL to verify that your PHP script is working fine. Fix any possible error before trying to send data through ESP8266.
Side Note: It is not recommended to use the API mysql, as it is deprecated and removed from new versions of php. See (http://php.net/manual/en/mysqlinfo.api.choosing.php)