SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ecbc626fbb6a9e32a1664c6b9b7b7e4a37802124b6ba9fb01a8df140132f938' 
  AND token = '7XWBXrboADd5tE/OUMzGwS6HwHRpKqEQp4/mT+pB7Sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}