SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6c61629864a5358249e21f98ed3b6a2d31ea813bd8768bf983242a831c8046' 
  AND token = 'JlwKC9lB/VjrBK0g5MwXvx79q9BBGUoXHzKdfW6hR/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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