SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13ff2ec5cfc211536b491af74c489b12a90b3bebe175e995aae8607356c28d88' 
  AND token = 'HYrGEzWvHD19qVhocJLLcmetBJ4hGKSxajVCUj37Qt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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