SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2167763c0631973931648989e973165930cda515e3cf915cc59583b8c7e6e1c' 
  AND token = '94hVfxxJh7JvmNY+sjZjbVWyArvP7n4CKsNk/GjuWJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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