SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff8991000ae7433d4303c6aca2df1aa6faee240f066fbf73413a899ebe72255b' 
  AND token = 'QOPsTSW0OlSPK+/GvcVVoUNVGjlTP9JThnPmqee9LTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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