SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca1a8feae68923fab784b72f3d1382d6895f19d3c4a26efc08f232dbd7ea6314' 
  AND token = 'fRChY/vOQIhGRIQMdZUKqvzfIVpsxRatNG0kvdz5bIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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