SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '544dd2bde1f4654f1df7dac0413efebc13d12b83b83beff4803e437cae3c13f9' 
  AND token = 'Bnagd8K9P7ZRXWpsc+Nd7RzR4Y/CekJTVX/A0sACchk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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