SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dbe7353b7d32eb754222a28ee7262e2ddbd760e38d3bb101d6373b3ce2f0e96' 
  AND token = '3tLPAxfazfLOJsZKrYtMIN1SW1+0wyYvBYxwJfTLMx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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