SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '907c4c642da327cabe264734d73fa45e11ac504afeb2ae097824b39f9b3fddb2' 
  AND token = 'MR5hEaqikqwCw2/3eahRJAGGGWrYtZZftsONHaVmNDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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