SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52fd7f21307f34ec98ba25978766bf130a54edc7ef0c63dd03a003c87a6d8b16' 
  AND token = 'rO36o+1JDFM8367qJ4gi6ZAojSY/HhwNtFOxu6orX0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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