Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a576c1e6099a36780db4a335c8b8cd624d083240ab4e0aa90eb69e2840d2ef2c' 
  AND token = '3mG+Y/BlVYY2l9/3uZM9yvs3Gzg0gsi/dZ4EOTgqLiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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