SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86b2b244528f10a846c4a326eaa2adc39953bf11e59e55ec8378a263cf9799d4' 
  AND token = 'hoRUF5S33vXawXM/A1TD//hzhhhiDRh7bgWmcmownqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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