SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6d47301dd174569c6f63d4000406dcc7a9cd91908e1888ede495b9df992ae81' 
  AND token = 'zk6zNEvv12HZ4Of/leh5VAwTUS/ZJhnbGBojhZXmgW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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