SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4079cfe3ccf5e17e0454a6b13143dcb19422b69d5e19bab6c876a33a6fdc2808' 
  AND token = 'zhcYHgbUczyMfBfOv0q1rBYQgQqJUgcuOdhfugh6SdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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