SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f135100a6608046b7ff9410aa55c5c9430c7d8a74e27a5513062f957466689' 
  AND token = 'eiSzGA8rYSsjZzZq1tud/br73roUI3/Sm7O9psVEBT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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