SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812829377c79634067da793525adc1c62441888ec1095c4e5b1eccbe943aa4a3' 
  AND token = 'lZLSCGrwUt/DUbX/P8EIjOh0ddfZgyxpOB7l7KG+7ME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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