SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab125c512f02e1a6ae310eeaf1123cbd74465812155fd65f75623c33f5b54dd' 
  AND token = 'NmhnqK67SxhQ1M4iRjRaKAuH67WdA9OHifyh07RfwaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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