SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38366cce01cb5036961f565a68f0767ce3475ed14f46e584815908e03683af39' 
  AND token = 'E5irxShJKAKs5l2zH8dNh+3jYKRROCtkNnw4psKw0Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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