SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b5dfeefdbc932863e0e331de78bddf61335b84603e4da90eeadc9cc4a06b4ea' 
  AND token = 'AB4y7PbSHT4tdl+DVFaDuGmw6/QqoHg2cIlNhm2lwRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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