SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec6429e683470f1a7aedddf53b00079ec6837c0cb5909539140230116558dac8' 
  AND token = 'YuT+HmUjf8anQ3/UQqNdc6r9WUjITRbg4ndeUeQXFrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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