SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73cf9addc7947aa7de369025bec2999fe54c648460ecbed7200643afa98bf8c4' 
  AND token = 'eKh9Q0MbjR2J/jyaynimV7vZZm/Uofqn6AfvXg6DHXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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