SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394625f03cb547b7659d63e02cef68e276da20f1212b13bf89d952bf8889eaa7' 
  AND token = 'qj2sfixuoA/f1yXWvgzuH1QG+pnhj3sqvmfjNLdoJHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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