SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5472f466322a11f22b3803fe881f68d225b887c9db17f438a00b8256b7b9013' 
  AND token = 'VFvSzHE3u9xbNNjY8q/5z1MyzGolK25wiBt0azVEKso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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