SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '701bd6054d933c1f3666cbf23a0e2125a275d23354c7400541b5982dce97d6ad' 
  AND token = 'cnyWVd1hKacWVSes2rWsVNuwrnq8QY6VB+lyojzlaoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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