SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8fc2860c2b87e1a344e79783c22f5ec6a27fa55d0f9f50a2c5f9a738863f20a' 
  AND token = 'u65lThISjpBpoUTpg+TcDXRi5uZShDOrZsq5Yz+lvvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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