SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3748f318345fbaa876ceb065e1e5e7e5197d6882162db03cd8f5663411f5f403' 
  AND token = 'TE+y/Yd2gCIaKtnW9VrHvhiklPxwDcA6mfFk7u27gPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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