SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93d178f4e09be4b8a5f1f82acbf9b380b79079a05ca726963312e9d0e3eac378' 
  AND token = 'pf7i46gwJH1wOg4dZnwOD+SXdIBEtG/iSmhY/eLPGSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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