SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc7fc7d6ae58fd6f1c6c38837a22533422d8900b45f5eed876ab93888fef9ed4' 
  AND token = 'h3aJ3II+nktFYxmWUz5Y3Zho0MAsOj2JqyVUvU5Rsw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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