SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e42745f262f9d803fc323112d6f555a8ed59702b92a201bf4a273a229beafc8' 
  AND token = 'RtmBKO/7ggA0QbSKNhYxv3ZkMY2qwInchv5GZkQ3I8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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