SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393972297136b5b988f6edf12782ea6238dafa4934791ffe59e4dd1e239f7cb1' 
  AND token = 'jplLC+lb8pWJBtqZfZiPHUort4B9TEY+snW8pwsTH7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00076

JSON explain

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