SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '994489d8d241fc3f4c54561ec34f39f2dab0bdebb6b4305db850f71e5715ec7a' 
  AND token = 'K3b42tjMq+xglmCOxSPiHNm7sDBKQ3m4/1ZvLXaVvLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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