SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2302d47ec46f4b5614b7a637f452b56790b9cdb79994316962696c34a32bbeae' 
  AND token = '5mtaZU/3iTF5IvUFZsk1Yh5DlqGtIy8nCGNGitXx0xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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