SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47f13e5f29e80e9d84f02d7ed3e8cf4829560c749a64545cc6cfa772d16f6297' 
  AND token = 'UGVZnrWvLttMAXrh9BTXEftLBYSvR//PfiOFWnFK4Tg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}