SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335f6d1a2950de5489dbe9e412e7897cd6d682f6a4cfcd7b2da29cb66b53d1ba' 
  AND token = 'chUcQWVYqnJZWK0pavagkeJ77XAfjvmoV8ERvhyIpFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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