Laravel can't connect to Mysql

[Дмитрий Кроль]

Введите код...runtime: php

env: flex

runtime_config:
  document_root: public

skip_files: 
    -.env

beta_settings:
    cloud_sql_instances: "ttttt-180713:europe-west1:ttt-mysql

env_variables:
  APP_LOG: errorlog
  APP_DEBUG: true
  APP_KEY: base64:oqUyw6PCgTeACFhautIOEx8Uia958GBodb4p+9KouVk=
  STORAGE_DIR: /tmp
  CACHE_DRIVER: database
  SESSION_DRIVER: database
  DB_CONNECTION: mysql
  DB_HOST: 127.0.0.1
  DB_PORT: 3306
  DB_DATABASE: ttttt
  DB_USERNAME: ttttt
  DB_PASSWORD: ''
  DB_SOCKET: "/cloudsql/ttttt-180713:europe-west1:ttt-mysql"

My app.yaml file.

What wrong with this file, but I can connect to mysql database.
Take this error all time:
No such file or directory (SQL: select * from `sessions` where `id` = Py1cww5h0EsVKhlxjypqAVCgfdL8F2od7pvzC6ZT limit 1)

Laravel version: 5.5.19

Trying to change different configurations.
Can anybody help?