SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54b354bab384eecd43e58900625f26a276fc49050aa5989f36f79a9beab68e3' 
  AND token = 'quKrYaqRw//Uvoz31TbZ7Bw0UsH6p0WwrrY8BPcdDTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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