SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49b53ca1dc1f6bbc1f7e058a3048cd2b7526ec8b3f7f55461524678ff63eac6' 
  AND token = 'NsNDpLcDdMKhAiIhzKvKWTw1TeM7yNSSef95yjSo1Uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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