SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3a90a5fc94203c67467403171aad6608436143cb2295bfc846c91ef4fdc53e4' 
  AND token = 'KBysrPXuBfZkwjF3Xsn7ZhwUNBhrznwtvvEPL02Wbb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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