SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a899cf49c9e6de945a3e6af59ebe021a334fe6420562a0b4c81a778af698f524' 
  AND token = 'hgBu0wn3Xi34/GV5u9xCAtLlMEj1li5d5z+Zq/6jSfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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