SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6be906825a82ea92717542204ee9e42177745bc361a77daadd5e06eb29d8d124' 
  AND token = 'gqKcv0GbaHYLOF2d5UOJqB8HDv8cSdBAthiN8v8NtBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}