SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f7da34ad4fe2831def81df7d7a75fc3785ff8c485ee48dc4d156763a945253a' 
  AND token = 'zB96OEwU5tH7pBAiTcRC7JoRV3nRwwNdpf46VyY9GTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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