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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2b38819412f6abd7d8fbf0e4b03b6943d6a3fca90ab5f875cb208d96322460a4' 
  AND token = 'KlAWsZuHteCNpimtHlkQkYP/o+FBYZ9LrrZTarYLb7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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