SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959c7893a05e3be3791da39388f0dbcee1e41220e76bbaafcf969c5c4141356a' 
  AND token = 'lysv9HQlXVQ5pd6rk8ET7Wd4OZOc+ov6IZTTAzidFLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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