SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1841e69f82097169209b9715a20c0ba10105e363c677df0f9732693f245e738f' 
  AND token = 'FNTmmNHnBz7IQGEaxZk+lU/kGGhiJFSDP8ja8KgCDZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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