SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d200358ff16cfd32b7861cb1fe01754404e08b5501765c1bbdab0da3aba492' 
  AND token = 'uR3NHdj3UI6xdK6kbWHgQs5grCle3bdXZknzU/TUno0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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