SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '184db2e0074688a14942e38e67bd3e31cdfe77755f2232a4a17e079eabcef118' 
  AND token = 'DZDMrdYcdiKlHvd6qQfoVeQZyiq+coO87v+jxYc0esY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}