SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ca4dcb14f7957394e925699fd40f69a8d28128ee6c7c347204994ceab431fde' 
  AND token = 'n6O/fqZ/r6L/pBrPDeLfgwUcbGB2SWZGY7LDb/Nt1fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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