SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c1f0eeaaf04c3cb26a8666f4320003465804966f1b3fafd5c41d644d6802909' 
  AND token = 'g7tnJlbHqynjqis5WCW4Gk1wDIjwFehgVH/XaJ1/+m8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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