SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '392c8b826991b2e82f5c3d553f71e3f91843b887c697c6b98cf4e114209106e8' 
  AND token = 'EJJzCwwh7ZZFVwFAc6NTc4ll4Y4Y+YVkoKjntjIZ/DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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