SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ff0366c77f95bc00558daf7e8a4854a0ce98483a4b2343c80218bf23b7801be' 
  AND token = '69tXQdBUrHuzI8i5xgByY1wSVJMYe/wdnQokFS0HZwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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