SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7871b0c3162190881dd2ddaefd1ba586a7bae40474a7a6993522714e383c012b' 
  AND token = 'iib5xFQqE6wmF91wKOrfzu/4PPlOI25XSjJphYPU/s4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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