SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fda188ef3635d5929ed9471f136038cbb88fcda9056741dc1c53de5946bfc27' 
  AND token = 'SsNtyZIZ0/aaP0m3u1jU29/DDaeFZ5ZSj/vWWw5lZi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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