SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1dc106af433de8cea7eef843e1e1e92f3275defcfadbb67584a03b043f7c89b' 
  AND token = 'tElv4i/QqLKMssdzuVk75VvJhC/jpKs3+5MjjFtSiqU=' 
  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"
    }
  }
}