SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '259a486bb313a3194b6ce2a8763c1f8e7d6f6218afb167ef555c3bf0d09f99da' 
  AND token = 'fDTpji14VfoKqnZOBblmwXE96vVhKTgqoFW19/7DzVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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