SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b26aa43ccedee427e4db7e28baa4830917115362f96f896a8aa7b32758b143f' 
  AND token = 'uWRDrLn4hBKK/zX4L6iL90BU4JJvji0jkuInlVpv8dQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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