SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1df9d3bfd30e10c075b80a19a2d88d4db325827a97bd2d9de73b28a26aad6ac2' 
  AND token = 'dZePP5mBSFxioAb5pcjOg3REMQL80r5pWZlzK/6e9GA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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