SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a00c78a61b3c371e62d3c57a5f8d8c7705f1cd8d7431b61d3e18655f419a0b85' 
  AND token = 'Mk4cnrqL5tUrxTOWpdCV6H4NEs0XnEst8kq4py8D/Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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