SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77bae555a50c22f7234b9c25bfe43ea0a32f03b262abb5fe342ac03299fe3f29' 
  AND token = 'NVQQIXgMacnfVKDkdj/GEOMcbG6makMgAyNd5P2diEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}