SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4a9605019be73635c93619e98b4c15f7f84e0b8f8e78da78b8f9af6c92528320' 
  AND token = '5K/VzCn33e2gdPiAfX3jusQHmGxrV2lSKV2TBm/B7yM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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