SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f21414872a0b246c49859633204df9781479395e175bc4245ca3dda2c65a98e1' 
  AND token = 'I01/vZQVvqlkapI/KSAZ2O/54izZK2Fwq1YBTergjU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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