SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9c530744e8aa94d5701e4c39996300ac98478578c5b37b3afcf16f0b6440d27' 
  AND token = 'Zi8VF3NIxvbbLz2yul9QnZZlXLi+lrVu+q2BT90w5hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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