SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcef213ab1ed720285482f6f2d3e4b26707febf386f456b7910460af4056e0d6' 
  AND token = 'JXxHmTio9cUXP9V0VTkw0yjpVgKLVS5sRkxxSxSnL1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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