SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d92fff00b7adfeb6a5b0b384685e8db333301076baa6e3ce7e279a93ad9ae24' 
  AND token = 'ZIkZ+WGdftuLT7IMBmiFKGuTkBaQM/msz1iDBl6PDFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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