SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9123c1eb936424452833099d648f9522bbc51a29a15febbcb79db55bbe36c30b' 
  AND token = 'QBbNZMbKAMv/aSbejLS47RIXkT+XkQvFtSCENXoTuTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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