SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e81b0243a9e1f0b51e6de69b5425e6be11801500a43e3261701360333a72b11' 
  AND token = 'voWcg6zS9SgCtDp6Eey+e5R2d5WoIVW+ss9iO14noeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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