SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72f2613168fd13956e90de962c480f390b66f10decd8308d16fecc8ebdf8abfb' 
  AND token = 'UVA8xkY/I+kHFfXDlYRPvlOGItvCmAri9SwbJdbyyEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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