SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bc6e72b39b39e772088e6677246910bf32e99995d67419a08fae2ef7571e207' 
  AND token = 'T3hvDqxFmDXy0F1G0/CvYiJdVwT6VrrCjO3qYAwm3MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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