SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ebd674d903ac417ba9526ca7cf8570c5f34d855941aec44a6c57923e1c0d3a' 
  AND token = 'ZmGFv+rfHcEJVf5qrDxCjCDKwjIjgrnuy596RRUHGuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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