SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47edf4fbf190519c49d23ebda606a69bd5d887f8e4ad0dff608f607006d596d7' 
  AND token = 'OsltekDCRcvZV9iuTfOe+Hn0ATDtjm8kkEtPAIvHnEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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