SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d29f4c9542054d508d4f6e158d665494b991cd9b51bce6a3ad0e94c867a916' 
  AND token = 'vUpv2VuXffOcUP5/wWKA8CZMgqagCJl39hpf3SyIXBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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