SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c39ef5dbe4943b17f40132669561a3b8bc7605247324eff8831d966ea77ec9fb' 
  AND token = 'VYJI3o4hfYLR2WUJIi/oEycUYBj0/WwDgxZTbjy8tx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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