SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a74cd912ffd57b109cc284a803ede39bea99c1a9c6014c2e2824e79519e0c3f' 
  AND token = 'tZAJ1nzHYPWjSsWz8ixUFZKeDBaiSZwCEcR5XjuUWjI=' 
  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"
    }
  }
}