SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36929862f0b10a42cd393f0dbb1e2186fab6b8d35fde5092f31eac018e598d30' 
  AND token = 'tUsJGjdMyFugDkVifkT/KumBHqvqlmhNqpkU6Y8xJ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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