SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '62f690bd879b611f459f65695d5219289325e55e6205a52c418ada88c8ab4395' 
  AND token = 'xnDJd904GPnJsF/Pi7rpXhoBkJ/l8epRlwtbIfr0RA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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