SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef7f7ea3f5327a378a135750561297a3a353ef40da2129035037857ccdd259d7' 
  AND token = '4ATvo/vGJ7uYh/80CvamkCHv1opSIA9lu7ANAuRwoIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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