SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '396b19d84841783ae34b2392ae32dde9014cc4fe3d06b797ea7730479ebd56d9' 
  AND token = 'Y3XBhmBJTmkGnNeEeTJJGiII+PLhDIaLyyU7Rj2pbyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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