SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752fae7553e767384358f31f052b60b3715b3f2537ca28d1997efca701b2598f' 
  AND token = 'NBjUW4CNls3LtwUTK4ZUghflTz615res8CJtzZOW/ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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