SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9280de02583f8e721f337fb42b0999278d762a5b36f3b2780c2a2c9b0fcb54f' 
  AND token = 'oDx8P8pywNsW9WWT2GmVof/4HaGvWs6ehPOrkshRbdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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