SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee944277c025d68cb94b53d35237129bc7c3424133755e38310ae08d42789588' 
  AND token = 'NqJcbfAbWMx/6AXvCUSb+jFFe/GZbhgB111BCBWq41w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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