SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24b18f86656800f97a29fb69d3479ebe1a2e69934fabc879b4212f8e9e748870' 
  AND token = '4Vi2R1e48um85s60qTKgxiy1Zn6nLjhO//QNMKm7JDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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