SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44578433dd1c08c4102d62529eb52b490337a5af7f36ed0b36a9bcc730b80c31' 
  AND token = '+Hqg8UtJBaaAgKlAI1qfeBBhxFIA4paJhqeQMXS4Xmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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