SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '992ed51b83b0e15e156daca4823cbbb43696d33f397955846463eb0f0d5de49b' 
  AND token = 'pARmgO+2rKzzU7kjCvFjK/khDZTFSDhRo90zyxQMs5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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