SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31751b629dcaa5864c90401b1e3cdd24a36fd0cc1c73d18327153118588a6ba5' 
  AND token = '9VpXMyf8fcgc+1LvXyFxXq9OtWcbTeSQlMHJgorKTYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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