SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89f8c4235f805f5026742249d4733fe249fe5eddb74224bda6b08a9ad842f094' 
  AND token = '4JanJaX+F8OMNXgIaRsTc3RzrMla6Z0EQvnrBFI1qK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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