SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f8327dd98d7cc3a3cc84e347de0a441e464a8889d7b523b38ba5482010b56e0' 
  AND token = 'fMcrIj31z62S5Zd0JZUeng00Mn9iUPnOIkHqfPStj8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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