SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59a208bca2022d574606da4189aa146c543114f6b2afdf43aac6a9da10aae39b' 
  AND token = '9iJFbvGSoMnWCOJMMP8PtQH3DmQUcnDjFy6B424oKxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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