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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ec4a3558ec1f868b036aba1c0c5a96b03167b07b6319dd86cb3541572250d6dd' 
  AND token = 'pw1/ARCtL7k9oQx4WfqHshwmrgctn5pA/qiFA5s8g9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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