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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d91fc1a43e879d8d6e4ccb73781e0af187c3fd7546a8a24c80fc30b7811ebfa' 
  AND token = '2WP3Hr2yQwRr+OOYnr9pIA1kHnnYm6biW1HWKAGYSDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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