SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ccb923ec05a345f211f7073866fa29008c53c3dfd638133ad7f193947d1db7f' 
  AND token = 'dtqOCPFtBj6pOZIaVKmkaktvEo3S+xPnClbAs4tQ6JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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