SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a6f162140f887ac2de0bcc59dcaf690957bb0bfa69778793f4863cadfd46b4' 
  AND token = 'Vk9jzKQ9+jULLJaPG1zujGIQqTiS6CPbF9cI8bSzZ0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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