SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e3c9924617dd65d8e85d0969d222555cb974c8f22385d078daf738b6b7daf33' 
  AND token = 'JjjwsAG4WAiuMoqdGiUAdScE0L8h5n3LNoAudH9/AmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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