SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d849d8ae8bd9f35a9a216f97fd5d60586337a84113a4131546913ec95aabf06' 
  AND token = 'nJmUNk6mLL36EcwhmyzYS5uCP/fUbOrGG1pZBerl0ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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