SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '356f7ed55341339165391e429789f93b44afe236aba0b25e1a24a59d6a23a3be' 
  AND token = 'Hz/+9XaEe2vqPfGzs6jAlAzPuIS83HDS+8TtnbKzDiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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