SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9c96c9cce82632afb54dbf404b5fcf2367480f526bf0014f2ac3d9d92921f150' 
  AND token = 'pJn6dg7VD+5H/VpbF7eGTqZXZB5J6QXpbpsiNAZJiO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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