SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d07b4d74afc7431f91adbe7900a819944924bbf4ca26930c38307af09d3b547' 
  AND token = 'YYFmBgzVEmseA/fYdc43uC5E8aYK4qHmA7EPgm8bkvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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