SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd7618541a1300d52b46f71f1e73f0df8abbf234a5864e810797f83401393c7a6' 
  AND token = 'PPAVZuk9nIWAhlxa8ZjuYP+JEokNGJTTwjQ2Y0TG7gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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