SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71d659c1a65675cb52fe91dadef02f5d798c741612326cb8b149175163fcd622' 
  AND token = 'T30l2YsLnijg40LmLdqkg1lbPN42nViwZuzO/6v+DGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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