SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e120850eb5206967a3c72fbe60ced7d3acc8e0d589dfb99bb6746b10de867c7' 
  AND token = 'Yq0Y2bVTf3G+rGpz9y7CpiwAulzvQB/FKW2KprnR/Bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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