SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b65ee81824c5dd14ddf52747040883aa90f2ba9ef308d4f19d04fa40967da9f' 
  AND token = 'uu85zRnqKyQBOZx7nyFb5nA1L8/qXl9L9DTni2svdgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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