SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9520813549cf97ca8ba6156f496a69095db85a6e63d9764dfcb763d8b1c4fc' 
  AND token = 'qJBHOV+hVGMdlN9hLL7vtAg1R/ag55IAw4Bum8DZPFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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