SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c421864af1eddb1106e8926274368baa9ef52b7c61f728cbbb4d8e5933091cd' 
  AND token = 'gpFjQPeDxMtymdZRoBJlBuLJZ4x2UlFwq/uaOPlbuNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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