SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ba6d44b1ef18177c3b861e6f3ebd30ab5747b0904a10f416372647d184bc7cb' 
  AND token = 'Qk3hbE6NXX83DT1gQWtiSCOKCippN2S7wnAnP8q1VUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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