SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30873e02c8ac1685703a317ee39556a949983b1ef7ebf21d2721bf78d680f0bd' 
  AND token = 'CaNOaZ95mlp/myB2yLYBqHgk8iOwJogvd84Z+SX0WwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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