SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea6865a4c26cb1808257dd09c9591b51049677af4a5a629d829b50f08efab20c' 
  AND token = 'z7kOR+HifEVODp9rPy+XbTSwBO7UKvgbtn8wlYVYJqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}