SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '018b1b140afbb4af6b4333407a3767419849bc6ca598215c63f102c714d574eb' 
  AND token = '21vysErlRCM8uBl4bO2KgAAmiuUOKJGro/9u+r3UcAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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