SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f27ab62c21694091d3c7fce79e9ec283259bceccd683ca516a5ce408c2492e1' 
  AND token = 'xvtWqHbLgMprFbohc9AX5gIo7eESqouOz2b2hmI+RY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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