SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2ea24a58841ee12ed23b056079a4a98cd7de538ac9f8135b3436b266d4f577d' 
  AND token = 'HT6ILmv/d+/yCrKy1AMs8uRI+XxZt/UaMKD3kOq0TJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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