SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'de30c2c68bb624b1998ae8fb28402250b57416b7cee443abc19d03e2625813db' 
  AND token = 'lv5bR/i6FgUVS3uKa1h2jVuoSVkVHoivKo0lrvmVV4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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