SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77cc9c0dc9f4f2cd6beb91b01947463a43c877a513d5f8c8884869c62ab5647e' 
  AND token = 'kvVbgshUmmj9gq7M0DlDEOJY6bggZj7lGzKHGb5hs3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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