SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56eddfbd48bb87d658d1ba9dbdbbf668bdf9208a720811930b5391e74ff13333' 
  AND token = 'Hj3GdDl45UbK6hAZajxKCDSfAjdzOrEUjmJNIHWh9GE=' 
  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"
    }
  }
}