SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '084535c7bb794c3b866211be166d1aa850ab46ad438044c0cc00ebf76aa201af' 
  AND token = '2fqCCYmXd2iLd3MbAr6eZZnA/Cx3c1qJ1InxEj6JHoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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