SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d8a0038ef379564745f43cf54de436bacd69a76a43ca00e7736bd1eafc4f71' 
  AND token = 'Si+vl/lVQqwcEVk8GLhIoB7r9K8nGqZz7BAHsJo/kLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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