SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81905abb8e9930fa17eb669b8a52dfc750b58c5cf1cab28c60043c45a8a05ed7' 
  AND token = 'ZXFHfxzdHwLitKxJ2ztcO8uoHsSJMzBFTnDI35Rn65M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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