SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac8e3ced3327875492eaece5aaccfd935ce88e876e07acd1e323ca54dd920bac' 
  AND token = 'VH9N9o+vovnHQjOybm2UW8W7GdIwzJcUw7pBtyjVxv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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