SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '01592c4f10adc148711b3dc8e7fa6b6b583ccee09b3d4a3725185488af9d2787' 
  AND token = '8cwV/ZsdRzx0jRWjG6MmZ2jSVwCUZbvGRiB0T3oKvSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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