SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c920fd38dd5f8e988f8953ab76105c72c578e893810806d987b34d47a0e5128' 
  AND token = '8s3nDFwKhf8rWg3lW7A2H5mhMGJJHZoUHpDMJMo5tmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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