SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd21c0c347c56ddde361c8f1fe29c4aa21882da567aaea33cc9c52ddd53a082' 
  AND token = 'hynzF/QTXQfXZDiEzq/+gLNkCVkrLSI9cP2Iv3tL21k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}