SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dc1a6843f7fe46d3d5a44f3592717e87dcca9017a2fb5b0a2ea96223f52bc40' 
  AND token = 'VMMG37oyZ97muCKAjBBUfjkpYMr3fuwGb+Y+Ok71XjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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