SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84b4e827ac03b98807949870a40729e2f05c47466d5c625b9a768988176f3517' 
  AND token = 'AUcyMd1MjJ/Cs0DTgrqhPkjV90bFjnUWIzeuXKfAJPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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