SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dff5ca15ddfde39bbb797126ba2cf1211ffd441cf8e2a8390779397e8511772b' 
  AND token = 'wsoD15FZpuvjX/gr7PblM3UUBrXJjS3DDHyt4tpvwhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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