SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9983a8332648e22122232a7f16800801ad25c633471df3d1b6f29fed886ebaf3' 
  AND token = 'm4vb0DQHaH/gZ/C7cU642n29WmkD8PzS/9jTynNshUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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