SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26c2e27178f131f4f8f5aeb11c5442f5b5b5a6f380289d57aef3520be447917f' 
  AND token = 'if/vlVkzM3ZJsqp2u7jK/dYXo7N8N+r97CBAFPcyNCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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