SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '921da1fe9e1e11d1293f3c0c1aac71c751d082c668769f02cb9ec1167c3f64fb' 
  AND token = 'IF+6ljh0PQ+WxKFcFrsWBfSgbXsBwl1m7B7r2XKMdCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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