SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '45e564f2413b2d34d84c40435250d1da2af71016ed4db39734c21c820588313f' 
  AND token = '3H9qGr1Z+aLSV3hIJP1+PfovC55fJUb8u6vmT0lSlGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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