SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8888409e2edb10933617cec999bd3990981c9e3ec874a51e3888235327253f05' 
  AND token = 'OF8kE6WNOrXfLdG/qzCd/HgSU43ZW3XPVJCsJJKLBw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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