SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ef4b5d3b570323bb2768bde5af2e80980da8980fc0759813191f24624460a31e' 
  AND token = 'ZDEk4MTlvZoKNaIta2zW75FnuvVZBE9udQP7EQtykfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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