SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7b48c464fca20694eb811edb809e7f810027a7edfb1fc6fdb58593c7c496933' 
  AND token = 'AMbhYip2JuxT5jH3Djgt4VwWRLcGbJsxV+uCjDoo7ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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