SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73e72971c25ad368ce8c462a15a0791fdb502d6fc110e943fb7bf96f1ae9b478' 
  AND token = 'iRpndSg5Hx8VADlbEUoWPUnE92xX2p7TCZMxUTeW5xE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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