SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c57502969d127088098bbcb95e8eedde14e2128c07568ee8b19eba6c19e537b' 
  AND token = 'mzyaPwGvOxDTrffw6gegmoAMEbO3sC7nPw0PrFDU2GI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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