SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ba63322c8afb87ca46bba646e97b303e3b27309e2e5bbd886a273de6f8d40e9' 
  AND token = 'vh6oWhJJThWIqzCQcjpmUnjfjwuViW1ZwbKoaB76tqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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