SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '096b84879f69afb19dee65a8254bd46c605d355f27704905b64ae22b3399a7e5' 
  AND token = 'gSwR4SMoBqoXO6iAzn/8z0usGonvZ+DTHohCdZixsEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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