SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a3189104c79b4d0a29f3af425c4a92ca87e970e653fd4b8d4859c22d5b6114' 
  AND token = 'tKs3xlGinQG8ncZIHINpUwwNshm4XeMpTDwqijcwahE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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