SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869f9fd23e3313152d3b773c8f1e887019d30924fbbee5de43e5de635fffdaa3' 
  AND token = 'tGNbgOzDD34k3YE4OKint15wGdm2C6WiVaM1PSxAzQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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