SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2ea439524739cbe9a15e8532d5b9360ef0d3012da5d8c64642b5a8bafe7b20' 
  AND token = 'V8jxp+saayKQNqqqza+j3PIWEWz/XoGjwBWiAyrTf+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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