SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1ee674ee027241f6a19ecb10358f42e3a117f12071b6a3c54ba517932415cb' 
  AND token = 'DmuQBWgp5XmBPUY9JKS2GcfMhceA2uasqPwWcIJYQzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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