SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bd7d9792aadb5278fc7612da872a308c774b69b8bb65b0c399f569fc4badf42' 
  AND token = 'N9xYgW4z/YN2S/ja5Ca/dLGMqHlCOGVgmbLiTiwS/Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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