SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4c39a0055daf6de09715dcabaf21eb244d906ce97074ddc8b2aedf8f2bdc0f2' 
  AND token = 'BvMGXOhRlGTtdpYMQR70+tbknihGxCfzmkCXGjKoWFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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