SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd9ae371f17c31ab17227541686789d2d428a69bdb1d7adbf0a36f08041407661' 
  AND token = 'ktP/BXBj2PG2tp/PDaChIveGrnzA6vKtRPJ/hb1UxYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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