SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c59e3ec40afdadc1776b286a2520ad2f5c842fbc92b72863fb54c18235ab254' 
  AND token = 'DOkcwM5HDZqR2VpNGDoZfUyFb/ydGgAeHjXmnWbAmO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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