SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a20c12424a58f593c89cbed20ced43e72e0fb07a8dc12bc9de43a8e13496b863' 
  AND token = 'v2NZohMD2Swi1+wkXZewYlTwnLxoPCLmeg6FqnacR4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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