SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd80c568aea9ff760bc08d94f1733bddd99e5dfa2a6d4a0930b058b2ee6467ff4' 
  AND token = 'N6KNkBg7xAByufnNCobtn91TmV0AkA+hfbUQ5YwGPvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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