SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '655a17ac9d4a859fa4f8b039f69ed2ba754b25fdf3b905b506a7efeeeca4a201' 
  AND token = 'JUGuLSpuBfNukp1V0ehxagIc7HliP3nIZLHZ6DFCXLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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