SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '520105bec274e1fb611acf9a16772ff0251f81ed05ac5f200397e610ebee82c8' 
  AND token = 'udU82p2NzjrhoKttJKuLovzx5LWeSoIg5toQ7Ii3srY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}