SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc56eb8460f6a364154b56c40bdaba407b32620d23ba3ba270fd3f9a420c6867' 
  AND token = 'j0WmnMRmeUZQAfubr9x4UEBpB/83PZIRNY4hihBjCow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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