SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '28faaecbb8cf0f65fcc64c756c968c9f79d6a9453cdb183b697d55cf24227199' 
  AND token = '3w+LNy0sxt2/8uIAl7StqzO42GTfUEV7WfuVbDdFDvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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