SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f49350fe14ec304f25926d6decd514a4110575caf47b2d0f5a60989ee21c85' 
  AND token = 'LCWmD1sok6lj1WtRaDaQIuuYDE6TdeOh25ZYMAeD5lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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