SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a37fe14111fe48e01f31657bb5ef806aeff7acb1b4b362c74bbb861c877932d8' 
  AND token = 'fis3qM9oPiK0DNWeeuIrYHdkLRzDQMieldzT3pfirh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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