SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a52037202420aab686fb32908c7e46a8600455f83352d54b70e9173b01161c' 
  AND token = 'rTkmjoYdNNfPaNqisMpAMEKKkLfF9DuqDG9WrebhyME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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