SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a52061ece769c0f89bd055ae4cb73c44e81886748126a24d6970456c04be4334' 
  AND token = 'XSDm5M9RJD/IvcWUyQzaMlt8lJ5c9Nl53QK2iSwAaDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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