SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f9bba8e9b1a9c65aea086aa542085ef93271af318e2c647b808f45ea7a0bbf9' 
  AND token = 'D6zauvgRHKSkYAhAhKKJuilaNoE+UaJyZgzsjRH+oGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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