SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b938ac286066030696709a3c703a6a5eedd084b6eaa64d2a1a632e7406900c2' 
  AND token = 'dIaY5Pu7Y5ewWxGIGMVSnWC4LeL2TxT450aMtfgqVi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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