SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a49a35fb7076ae1f1b7d2da14546d9280879ca218a6a2f68bb9aa5223641d47' 
  AND token = 'bTKU5KGqnqq88sQKquBm3bM/I6CEXERp+lwvAATLmSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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