SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4947da5f18df56e7f36dd1a0ba959fd3e790b6efb540864b64aacca94dfbb53d' 
  AND token = 'BjXGYPxUwIYDqHM+s4Mp4K2akXNe+/RnTmVaRI/MLGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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