SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640721ad25f17c56f96a6e3078c816e33d206e4eda6d58b585a8fba1d840280a' 
  AND token = '1gMG298EDv10itWOw5+EHpkyZNjy8fbX1yahiNWl/Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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