SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0c48046045704543209952c04f617a55e59c4239d689248ea544b95bd0d050' 
  AND token = 'rcOYuCj3wC/NPNzQMC79vgOxzrzv7KPEa6X8YGXmlGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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