SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c17d45e62606549532cb453c553923a03ee7a108dc3d964363750a55bc961945' 
  AND token = 'Dl32kVJa1IeuqChpsSVq3qCVwxPs2K70yJEWO4ZHiaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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