SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de4b7f77f83ebb937b06971d852c0878cb7096afe5b51cd79fa484e434b38d54' 
  AND token = 'QTvKSG+whOdvzmPN8PzRv79EnsorVkm7QpjHOLTpUCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}