SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e9f274ba33b66b9439eaaaa3b0d362310a70404dbba26117d822e648d0a23c5' 
  AND token = 'AsslI58DicZsMYtPIqUDYZQzKd/xeHUG3o8AEGv3oJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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