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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd3b10b02483ea07e49be6f20bdeceda4d3672334f92869e33381a9e5cbf68dcd' 
  AND token = 'XAKAEXzB2C73SiFy00ioh5bXOV20xTf82sZIEw/9kK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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