SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6439b6e6914299f7ce57121108ba182bccd6e8e978dde12f35ab9a0e69bf56a' 
  AND token = 'oQCIiPrC/Umz20gVaP4UOzahl9d0xmaprlEK7DxSp4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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