SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b32729858ff1fbc7abd691cd64efc7616cf783c1c586f7dd1a9a9d3307023141' 
  AND token = 'XOByVHdemiJ1oWaszwc///T+A3HLOcaAFJYTIzvsGwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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