SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59e8fddb3331eaa947efacec316543c8c694da8ae110f3d3d822c4a3ce231254' 
  AND token = 'YJ7DikFK69RYCGBvlRVf2BwajaCW8Bkhtqh1m3PGP9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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