SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4341769338a541d03558c351a452c21563c3a17417802d4a2cefd3c5f4b62b39' 
  AND token = 'hpEtfVvXvrWzf4KM98xp3X3WJEM97ISbO4QXOYXdoBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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