SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15da0e6f7d2a4165f2f8dc2d47c3b5b60fde9b756dc51b53c0976dcc22c46abe' 
  AND token = 'EjRANzAG6VN/5KYIlhYc+2+G8ColyPQl1zrSzlNJxZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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