SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1be6e97bce37b9a44b707ef8573b8b8e796f16a3e4657ce3802c583dcf42822' 
  AND token = 'JNtfOd2TEzeyYpgravhkgTey8+EPRfvMyDV+6txbqmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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