SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f9694ced43353a037b1b9d92be65bfea7a3a1cb2a3e869a1aa8c4774a897eb8' 
  AND token = 'k6QqmrYtB4Xmo75c/oFQBOHX19KEzJWV6CccAhpOHKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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