SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7710039e896f3d6362d9a88254e03935008c73faa2779246fe6dabb6a625673' 
  AND token = '5equv+JbfMq9MQjOiZWkenejs+uOU2ksC6N90xPCDLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}