SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eef555654d92b3d5f2e91db68ef1a89fea0b136ac94d84a3e0d647a9be9865f' 
  AND token = 'lB7Dv+FqjC3j+7VHeR6d6G3n2ijB+NwFByJWsQQ1osU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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