SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a2fc8d62ecce236b10f75733a8afe2bbd69955472d77b0f094b581eae120ce7' 
  AND token = 'VrZ4aXmYHrjG8Bkt4w6uzdvy4epFFCBm37ylsziF2sw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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