SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00f768709acacb25ab4415f80fbb948cfc20a14c86d161d861738f78fe4f8e26' 
  AND token = 'eBxW8ffbAJY0ktvn+jya76WWHRHpYxHalAMUfdJBMXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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