SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccd339e59ba52b39878a57925876b5b47190042647bfff9043d460d7bf942182' 
  AND token = 'D1eJNT0wdKX6pP3ct8YK+BOws6pUZ+nh/AOV+ZgIXIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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