SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '907bd5d9392d9576135b91f7da38460ea037810a754053890ce95fad3046f63c' 
  AND token = '1RojBRkT8KCEb03DUuvnECMp44ST1oTKksFRzPYXnzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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