SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaae00507057b79a13be3c226078f5e44d96d157679880a85f274116cdeb73c0' 
  AND token = 'C9UeEcv+NnoW0cBnW5ywCAdaFNibDVATCN6sTAhBYeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}