SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd1b2579c2bc134771b4dc1bf4f3abd806be93123e163e6f68e96fb3f7a7e80' 
  AND token = 'j4oiDqT6hGxOPaW+ZzVluTHBz7n82sD3jT9sHXDMjUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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