SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3532699afccb2861ddbfc08d84aade16f11b9792cfe57860d1efa704b5461f14' 
  AND token = '4Pz0GVm1tsZro6hjwpuKFZg1j3YCjbT8UvgwjuciJTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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