SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc220c001d5ce42a746ab7d79894f7c0e8d9e7a0219b5fd258a88d4294a93c6' 
  AND token = 'OL0eG08gr5lC8+y1xv0Qz/KSYYrXv8AQg+UwEuLQ48k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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