SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83129a55944fd73f53d3f87c6ee1572e43f8de6faef92657e6642fc3ffea26f6' 
  AND token = 'a38v7X30MeyhXrbKGzvukyNFF292UgjbEnmiSMqr+LY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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