SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47d32a20943633c70d28fc3d996ff415bb3422c0f991db200cae0e0c1b46f369' 
  AND token = 'oK5U0hGWXY8kvjdPOfUCNO+3h5QUab5mwQtPzRpu61g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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