SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8955c29c1bc35f5b21786e9ffb339e047605bbf44b51d6daae8eff80d4619d8a' 
  AND token = 'ZO0SoesJQXp6imJWq0fuJzUs6KzIVC5FkKkdmwN7JBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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