SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c577b2ca000a2e1ce26b1c127940f50b841c487692a6fac949b335bb83e2d0ae' 
  AND token = 'hU8Ne6aqqQTpR7XEi9AZwDE2sfq0nypd367ow9lvGZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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