SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c2978985176b2f7fc24a2c3e7ecde5116830ba9337bd9c4b4f0721da300aba' 
  AND token = 'YPjnuoDb3KiKcVgE3G3UqQXnUfRVrO5OuMQTqHqrMxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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