SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c3b95c9c7da8b523b822b53f349a5083a8f9055e5d93caa284b2baeb45f468e6' 
  AND token = 'raPE6ce/MB/PzroK1byK0exx0mLW0Ni6Q+Lj+K3gsg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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