SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adc9d2903a732a365efec36fc0ac0fd300cb7668d706a830112d745af27cc284' 
  AND token = '70hozknSJoBQvrONag1Om9Oaw5YmzdSLHlJFjhdmaLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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