SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44cd55b01f4ca8c51d3b1cf6b7b0aeddd009b386611faae39415123356191ee4' 
  AND token = 'pUE79c0z6AOKWURxmJGKvlvFhCxy/Jo+21I/fnygvTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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