SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ca5749ebf6945eff3055610304fb2c97fe5d80d533b1e9fd974c6fe799535e' 
  AND token = 'mWRetz7nvn6QgScO09lATZ1XwIwSL3VBKl82B1QMzVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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