SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '09c4c7101ce8839e8ff64a0f055b4d37e63a300cdb0aed429118cd350fd6739e' 
  AND token = 'zwBWl4JYQKmRA4Xu9BVkiYq4BmZ4lghkenaWqqGUbQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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