SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e81842d36fbf04e945d95b6208f652e7f21b6412d7cd32a06fcf538752e1ffc6' 
  AND token = 'UXJbhe6JvRpF7eqSMWA0cW63INfmWRwQHXVBephck7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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