SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278d451c9cf0b9e9e9da23796e863dc3b1c89dbea23c835c8f4f50a7d571f710' 
  AND token = 'bavBoYYqRkkZx/ZJSoC+pjm32qi9xIEN/JtVdhlUWCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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