SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dbef21bdb23ac64aa8095e9e3d4d108cb48338abf84b77035ad4835eadd3640' 
  AND token = '8uTAWRlTjfLGCYRwjZO3kJQkMqMKrZkhePud6GkYyDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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