SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c3a562116af196a46c6a29ec36a4dac894f50d84f54581d92647ad25299ed31' 
  AND token = '7KbFVPvOcYnykZwKg3X2+8wzCki/Ji/TGYgUo/EscKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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