SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cf7b2c607ba5f3b511ee4ff2b9f20b7f07e66ea1ddb3f4bf3463078ec8a62be' 
  AND token = 'XU5zLoHxKRb+K/D+JHEzlHCBi5zlI4TW3QhodKsM+Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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