SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c92dad52b74394595899545eaaaeadc4b0e88fb4bc53778a1219f30b730bb16' 
  AND token = 'Bz64qu4lOFE8MkzBHvpIElbtYZyxTNzRNylmFIngxb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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