SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc2ba79fcab1105026e4058a8ba71313e59745cebf1436e7e15bb1fb35d5ce4' 
  AND token = 'b7TcU2SssXiY1Cu3w1bslgZWeED1qY+bA4a/TRYSFfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}