SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9b2f58027f22ff182e888c72d20bd4e347b0ccb568ee51951727c42ecacd21dd' 
  AND token = 'DeqMA371UB+VTcbdie+w84cYy5cZGuD/YZe2TLLiyFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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