SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bab73b34ff3bce5c4b08a03e7fc02214aa099899cbff1031cdcef8dd7dd58083' 
  AND token = 'LtLV0dwwWqNPCVLvjVbMhcGYv+cYp53GEeMw6DKPs1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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