SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991ec894f423a9d613de88419b20f359466fd90502ab6cb6e85e50feba8ab8d9' 
  AND token = 'joKRfpCuc11DcXQhTSy3Lpribx15/rwtF115m5xLiB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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