SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a29e0abc0feeb100a3a901ba99085d79f03b2109f56129f6d959dee83c925706' 
  AND token = 'v4qXg/EAEShuoBNCX9rWg+GXG0pBqreJi8ACZ/vuAX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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