SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aaf85f22cdd429ddbb6e2023505cf41c9da28ec89fac5c066a3a9957fdd0789' 
  AND token = 'GtRvgoVlIegGj+FIfATf4H1ytWgBJccHh5vDQ2eIjUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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