SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cde427a2911cbee1ca116cad79989e1780e15fe93bd9843c0cbc73093408595' 
  AND token = 'DSy7lHsQBNJVsvj1C38B4fyNv4jUVSIk4hmrdGpThZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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