SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '80e712366af390eff2dfdcab9cfa07a221841680a1f5642774ea7a5c8dbd1d06' 
  AND token = '5Vkxs2nfue5BHhxfon/13hXZZiDV4VCr2Agj/UWbNxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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