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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7cdf8fde5fd154ca8fdf0063ef13040f3b856ff546af0d54f15cfbd143b58ff' 
  AND token = 'z8i3JMZTcjDUTo8aVc5S6+4E1Hwca+taRnrE4blAANg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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