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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dc3b28a320372a2b74f2b693d9f9f33d2d3295e4ab94dec199d5b429f7b0584f' 
  AND token = '6fwXcU6zdIYt76am1hmPFlO8Z8SO1E0HV1KAneW//XQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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