SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3248454d4502041a5011f87844107c6632cba14a5e74ea70d494d88f349759' 
  AND token = '6lD9zNRTFaRJGEBdiY3zmtUvVqzv2fgNjr7JlhD4rwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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