SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ae82e532d141ad3e8c226ed3553ec961e276ec942140f9f769ffea4d54fd5f' 
  AND token = 'sobxTmZXWUTxwLxy/V4u344zwK5yVSr+WKdjDLyXFA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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