SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2f48fa177ed66392137ffcde7f57d241ff435b3e93157f9f38017243cb345bf' 
  AND token = '6gXvMwym8mKtkW6kCMZMFslI0rWqiFkxncS5HYOpViw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}