SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '747e051af967326155d0821631892061e38991cb88b9fa11686769281ac0c0c6' 
  AND token = 'BGKrMSn+I9OZzhsstVFJFjXyodCqNGGCmYRaa0lf7kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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