SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '539feeafe877d3616ca6f4b5e93f5fbae8c8dcaba40c3bc47ce018ac11ba75e9' 
  AND token = 'wMd1ORQ8WTHsMp6KoJMoX0SZOKebvLXeZDTktHpEs3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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