SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af39e4a12ecc9ea7a83d7866851318e4920479e10d5f5d3f44ebd977d2585e39' 
  AND token = '5ZCw0LV9zCukPHBkQWAOK3WG2IbqNo/YUD/lyINAFWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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