SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf322f495c3886e6e0164b65909f336c078d026b6382afa0ec44edee8a1e5b19' 
  AND token = 'NKE+xjyQEhmyVCjxai9UimtWN8tKpwisSMNsL1qTs00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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