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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a74a4e73f63e099ce21fd0297c1553a2029a5f36e4adcd66ff8d433a38729ab' 
  AND token = 'iqbxuKt/82Bmv7LvlMbd12Wdkt5QcUdehMpYmO8NE2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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