SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3368a631bf8ee0f8857153ba168c7cea6edf45047b1c7177366d5aca5c63eb5' 
  AND token = 'WEl/NyKktxL/VbgevnC/F32Wq9YhgaTbgrUZRTKxUWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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