SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25bc15daa6db2749f9aa8a583a308567970a94a90edfcf41902c5736460a5396' 
  AND token = 'xmTuzqS+SObIJCCYROLQWDKA+UjXtvEo9GzCLtIhXdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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