SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9aad74a2082945f8473b9f726d4551b5a47f6e2e7b08b08354ad74769e5f8574' 
  AND token = 'jkukJYvzt3XIeTBsQKSQulLaDXXR/wE3uHIt1hzmL8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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