SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7506e982a51fe965507226c6782d4c9439f961266324226fd812b852e0654773' 
  AND token = 'nwBwGDwEbNPDIZCsB6tkA/12jH8+zCeM82xIf+k91Bo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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