SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdf75d990dbf4bc252862f31e473d22eaeed454861f22d25da4d05308f0a5691' 
  AND token = '283LRTIThsnqTI+AQGtzqKzUj4M7Sczk+E/UpbkdFPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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