SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc67a9cce9d9605a5369b8e1d2195d2446c7b145b1df15afdec34d192449cd9' 
  AND token = '0qV7MYNsEfTCGJ/KfLeP72KZZnxQGR+trlRB8dWVp1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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