SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8eead9f193cd6d5c1b73cfec65062ad5b40812e72c8f1914870f47a7a8b398' 
  AND token = '85DnxHcXRZ2dyZHlMEZCXDO/ivNVTCZZ0Kbd9uIwomY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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