SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6eabfff9338d23625bab782bf01c3dd1e9d2e948ceeed25067f24bb8e51fe773' 
  AND token = 'U6lH1CKcOyWPNSQPukyxGj+ZsYqTvoY4FEmi3IJoIns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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