SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38c90778071ded66d984f3ae2576b9d18734439017a1e9f9b5ad2a4763eb70a7' 
  AND token = 'NkmCYtGS7DQ2PRwMSzP98btAPIVQvOZHfrqoo5enyQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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