SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e77aaf27d27c6638b23fa98dc4397920f51b11c1c44203a8d2a5f61617beb36f' 
  AND token = 'XyVJfVd7ta9/8UhZdJ4752xrU/1h+unKvdwn+/8mdJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}