SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eafc3d68519ad509ea00d68319a6468243a921555050b356644577d2bf3f7b86' 
  AND token = 'hfGqhckvazShtHhCyivAxD49K9Yz2fKYryeh6qoBV1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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