SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17cff5415927ae320548b2e30283a2fa1f61b4e36390160c94b69fddbf190d6' 
  AND token = 'YmbfN4ulhDpmJfwAzXF/eFL0GzD8vRHXeOa0S+iKwrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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