SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a4731a5f55f4484b199dde02ad8156bc7a9881dc80eba08bf47a4debb2a8be' 
  AND token = '3944RcgWKvL4y8mUygJxlhZTVsrCgHSsPcArrH+VsU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}