SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ad2ba6a8851db79781249ce34edb1433d930de43ae1747efd3f36c674a1901a' 
  AND token = 'Z7E5EA3yDxmR5co9pw4e59Yg/xbuBteow4jraJThCUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}