SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b760557ebe1cae5e777fe4daee023cfa733ebebde2a781fb2e091c55fc8e1c8e' 
  AND token = '72KMfpabsdl11KdMdaVn9o33k6KznMHUrFS98EcQxA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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