SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1ce533222825142b4440d02fd168255f5e9f3174174164d56f176b67ba73c0f' 
  AND token = 'nkN2M+heO9aKWjMi8GSLlOabpdmXLB69DnqN/TvvNpU=' 
  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"
    }
  }
}