SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71d707a37859e984f7723b0bff3882d46085d4296cd4c7f6e2dba33f8c66e31b' 
  AND token = 'fulzP6bUS3pGtfhB+pUS+lUIzLhKIQYzlKuDChNP8sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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