SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a32c38ea802d8752e590457db555f419138e06ba9cbc89bfa95d15ec858f7b' 
  AND token = 'UaU6GYFL5ETYQBiLyH0yLJl91S2yxdplT76qf5frsOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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