SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '558e052aa66d853d023edf6371af2a836be01db46f92520060f8b86263bcc237' 
  AND token = 'QxLCXLLiQNrPPu2dkPLIAAxZW01Obig8BpLH9gD8d6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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