SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c30f87fe9f3ab09874a94b251987f376c64ef56bf7c07bcb708a78de6d648606' 
  AND token = '3HZkKbXC1PJ/2sQeqCy4OALKqlwLM8P+hFed03C0xdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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