SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de33adecbee52f44947e601116d413e1650baf73cc70d5cb152371e80c913777' 
  AND token = 'XDFrcn7iw6CsIDeFIPTRHsgTQhgJcORlgZ/mVWL49PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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