SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ddaaf99a954b530b4f20dc9f48dd698116a9cfebb7b89ca592e5c7906ba50f' 
  AND token = 'a5FZrkHpViYjUOzHGksVyqwd+X97q7aTeq7HFmljiRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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