SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc2f3bf97549db10d48ff25e684ebe1c6673f373f97d9b6d639d7c556559026c' 
  AND token = 'PI1hRf8UxLk+Lg04hgRlJYw24Kh1giPRYObH9JqQ8E8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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