SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4d7dca4cd62dd63028cebb157f675d4f12ec253730f682305684de72ef7f636' 
  AND token = 'JEsKquLwiaXsBUl50fFUa0jjxvXswuYBBomhMBuHSEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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