SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b6a5d53faefea05c15a73c78525304dd61f834ef64c6ba70c51b44d30f878a' 
  AND token = 'XfXT+hQ3OsL4apRXjjfCdZpb35DsshYOif/ehx9Mlcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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