SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '001339539bbd5e9edbf9d949f12d2169276a05e135c2847427ecaafeea2bf338' 
  AND token = 'nePIq6TvvS2Vjw/9nDAj9MCjpZj5SiursdLPUKFTxXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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