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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '742f6fd0453b829c658f6e4098f72c1776ced9d2b97bdc042905d02643822a40' 
  AND token = 'n2DmQTgB7XE67EO5fq8Swyxad19AiKaqd+8KEVbqQxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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