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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ac643874979da2f23194acf797bebacadbc53d3f48cec09464d3463eff5276bc' 
  AND token = 'tOKvcWkjt/Wd/TkO1QZP+j3S5m5B8VHe9DibSSds5OQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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