SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5863e433a8305ec7d3333037741bde4d405ddbabac553b7acf9a0d85bab846b' 
  AND token = 'r82tp6z0kiwOLly4KU4aURChm03DhQt+uR3ZhlvZRM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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