SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c9a376a44cc7a8e5e2486197e2ad316b8f72f1b128746a8d51a5537aeb88c8d' 
  AND token = 'oHL+vGnxr3md1HVkqNv+h3JmNjL3GwATKPv9w6hRpd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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