SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '86fc09011778203b7c39d5b153b7d433e680f61263eb0b06821b4f21821632cd' 
  AND token = '6rPOCj39++PZBCsVDjlPFk6vf53MgxMsuZLJdKB7jJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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