SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '309e5577ff91003b0622458a06c6b2d05cfedb45f4392f740ad2b031ef21a1be' 
  AND token = 'pRv0kV5zf8tph3d/dwKQmbWllhPNJU/B+mq1yXUVr6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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