SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ab1f04a931fd4153035d73a0da4d6045f2c6defc1bf969b9adb48c429798513' 
  AND token = 'UItBgmD3034O/RdeRrQqwvQy5qHIlsq1zQPBqpFjE5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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