SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc47a1059da7102884f92723e07a3f2e7255e367bd5a3ab5ba99853e1a069f22' 
  AND token = 'TvBunVLzDO45ZA5BCwBgub9lFlpqqYKjXUH6LiIvHNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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