SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83e8bd314c5fb0662eb08a77c6e6ce4ce9a12abdca64fb879692042d4e991ef4' 
  AND token = 'UdQ5TY/ww/LBlEU01+DYI81Ecft10BsW5UhTE7acTTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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