SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40dc1b5ac25944b4c9369c51a1118c26fea14caf54341d349e026f3691abd5c5' 
  AND token = 'HyKh0+nygJXVZV7Rlf26cCGBnmg684nq+CetXM6Yg/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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