SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2aff02b177cab3b199e8297aba13afe13e316183ce1410eedf85f09fc8471516' 
  AND token = 'kJQjr+wJTJ2vPRiG7DNPtqeLQEhYETWYTzmkmO/bZbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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