SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6fbe0aa2d4550ae8350145e70ca532790438dfb0c4039fc299c2952126cafce' 
  AND token = '0dFYsH7uH/gDJMOYbOVh7NYUAnaWDHvrLNHSKooFIJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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