SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eda3b747ce3e6805c281f08c7736c282c42fb9cedf04d13f37fdeff67612eb39' 
  AND token = 'FHS17BtTHwjtkh9w+PO7KzshziZfLpHwQbVU/z3u0WE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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