SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf4e828b12b6b172d4cbc88fddd832027290beaf5a7891deee777e68d999f657' 
  AND token = 'bY2Nldory2QuqEkVGIfr1fqAcQvVL8hCXUVSLuuittI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}