SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a4056653dd1ec5daab2d01db9c054411f56c8e3fca36f6aaedbc59b9f34eed26' 
  AND token = '6ktJb8tepR0/BoEszYL8g9p8E6GSkPeEbM4Eip0ox20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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