SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1e78683ba5461bf66c03072bbd61a6683035875910034febec24d88b440f74' 
  AND token = 'IqK8MAMNvot6vioR2fzOZax9DgBrJ9PB6E9tIJ8OBhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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