SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '79cbef92cc4983efbb70ab53626a207e5ee59eae412d71d8eb0f11a25cc4d734' 
  AND token = 'QzFrdWuIGvA3RBd+7YM3Vlkv/LX7jVxbwOrKH0/DrqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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