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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5383a692b294258f1628eb8196ffe7ecf6dec9dfb8b5ef5b59d84ea97ed39c1e' 
  AND token = 'xIiDO19jMzzdjctKWUuDfcsKi+AEbj650v7W0M3QJrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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