SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11a817f1c3526e4c1df68264f298c7b2b78006332ac2b23096b06fc286ab17d' 
  AND token = 'PWazQaTRxhZxhYT12j/BjCidyoTMYxjm+cpZSlqYGG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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