SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '508a10182b8260645ee569af92a1f2d9d2cb4c8e1f306b30d61fb6cbca58ad12' 
  AND token = 'BZGziPuEjcVMLTG6GwjRSUFdFpEM8pQw+zc4Yshafs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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