SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc15fc93faf536344709a71e28b0dae222d280459afc9820e2a486c15a5dd046' 
  AND token = 'rwgMF8aa/Jj2SsZDz9hpK2MekKxBMzq6rBvfap0N/jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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