SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9c6e4af89cd1623e4bb4a0ba7f4160ee5c1d487fdf3ae8087bc62f81b00144fd' 
  AND token = '2OEtNnXRxUdhdDRu6lWAY7RhudCYte1NWLAqg4Pr/GQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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