SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2731e4adbbc91239c0b96d3929f3cfc13f42794c3cd79babd0f754897ec466a3' 
  AND token = '3WZmRKCcQ+LLz5DlH9gtS6oipTiBZhob6OVAwDZQj4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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