SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa3896bb66d5b034d670b50a75ed47fab507d430c2c9d42c28346042211d2221' 
  AND token = 'vfEdOPi08yAbdpXekZk+MQ36HUphEeksweCIOf90MYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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