SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e826e9bbdd9be19e64723dbdcd400461be3497d446eb7372e3f0977d84518b48' 
  AND token = 'MVUJhtsjdpFJgIDJo/gt60bUk0mLpj5oewdn4+LNsjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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