SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66dc18f4839b65696195f58baf8f04c2c7be4642741f945efe7b9eab9dcf6c01' 
  AND token = 'JUowvsYtfgzKxt1BZt5yNwJy3/czt5DsM8KO1jqD6J0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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