SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcff71338e82214f7de00acf88ce3955992fb4d1f4f943f97d205b838f7ea427' 
  AND token = 'U1PYK6KyXAyn5xuJpPyfszpiwhVlq4vLHbUAfVqvu6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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