SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419cc0f923023918c7706ade8c98a8a0b96854a5cd2f8496bf4ad331c5674a05' 
  AND token = 'LBrvnucJ1h074iLzUQyUB3LFliTaT/qUZG8dw4j+WXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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