SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e44a6df69f829a74487cc92461baa55c1289210176e838c8f0009c461d67d9d2' 
  AND token = '5dV1qpOAWCYkhnG9BMGV+FsjCOTi2KrDbZ8Fr5wOWu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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