SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16dc64a65989a68a0c5cb07f176f729155c23a685b6d4044ad36184a97f1c594' 
  AND token = 'es6vPwD5ZJZviROmYKY/An51ppSvNEXBqyoshT8kZmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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