SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd0a474ed3308e789bc858a4418d8f3651051e252ee2657ac05cf4137fbbd19d' 
  AND token = 'SHVYbayxe43Jmuu6mzXN4MIlEJq316UvPUSwLfT6xkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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