SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f6c96f8c466367de5ba3109d424bbd9a000afb4a4337fef5b23fbe6f7828ac2' 
  AND token = 'xin2eilbEits0/YE5ucCoy2jVUTjt4aiVOo+MjS9tz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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