SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d8bb716ceffcec5408a06a8bfb859e8a01c21abdbbdb4a68140fe8f0f789fc8' 
  AND token = 'oPuK3yiIh5SI45Io4p8n1RlqHgcjntVkSk/T4BPzCsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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