SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1846568ad8299b3b7e62887606b0b72a9ba0a2788e74f2ba996bca048c3fcba9' 
  AND token = 'Ylyn70ppAJLfc/4T+4ZnmydTlQ5qyY1ZyxykqO/lwaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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