SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3ac9a448762f96c8738728c56f6dc5fc52f34eceba2a9849d9903811981ad0d3' 
  AND token = 'SlyqXuTw0axAFgZVusisDB9Oh5PQ6MP0eLyGziXycIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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